As far as I can tell (usual disclaimer: I am not very familiar with 3rd or 4th edition D&D, at least not from a DM's perspective), the term "adventuring day", as defined by D&D, originated with 5th edition. From the 5e DMG (page 84):
Assuming typical adventuring conditions and average luck, most adventuring parties can handle about six to eight medium or hard encounters in a day. If the adventure has more easy encounters, the adventurers can get through more. If it has more deadly encounters, they can handle fewer.
In the same way you figure out the difficulty of an encounter, you can use the XP values of monsters and other opponents in an adventure as a guideline for how far the party is likely to progress.
For each character in the party, use the Adventuring Day XP table to estimate how much XP that character is expected to earn in a day. Add together the values of all party members to get a total for the party's adventuring day. This provides a rough estimate of the adjusted XP value for encounters the party can handle before the characters will need to take a long rest.
Since XP is tied to Challenge Rating, and CR is (allegedly) tied to how difficult a monster or other challenge is to overcome, XP is used as a measure of how many and what degree of challenges a given group of player characters can overcome before needing to take a long rest - this collection of challenges per long rest is then called an "adventuring day". (Note that the DM is intended to award XP to the players for overcoming challenges of all kinds, and not just monsters - thus, an entire "adventuring day" could also be spent exploring a dungeon or talking to NPCs, so long as doing so is challenging and requires expending resources.)
Because the adventuring day is simply a measure of how much challenge a group of characters can overcome before needing to take a long rest, an adventuring "day" needn't be a day at all. If a DM instead prefers to use the "gritty realism" resting variant detailed in the DMG (page 267), an adventuring "day" is instead any period interrupted by a week's worth of rest - it could be a day, a week, a month, a very long year, or even a merciless lifetime. Even if the DM uses the default rule - in which a long rest is 8 hours (6 hours of sleep and 2 hours of light activity) - an adventuring "day" can be much longer than a single day, if for some reason the characters are prevented from resting. Perhaps an antagonistic illusionist is haunting their dreams.
The point of all this is to illustrate that D&D 5e is a game that relies on attrition to create true challenges. Well-rested player characters have a lot of hit points and spells, and other abilities that they can use to soften, overcome, or utterly trivialize challenges - even "deadly" ones. However, they have a finite amount of these resources that they can use each "day". Challenges become harder as the "day" goes on, because fewer resources are available. Eventually, resource-depleted characters will encounter something truly challenging - life-threatening, even.
This is how it's supposed to work, anyway - the player characters push their luck as their resources dwindle, and it's a matter of player skill to determine when would be the wisest point to stop and recuperate. But if all of a character's resources are regained on a rest, and characters are more powerful when well-rested, isn't it wisest and most prudent to simply rest after every resource expenditure? This results in what is frequently referred to as "the 15-minute adventuring day".
Let me clarify exactly what I mean by that. I have seen some people get hung up on the "15-minute" part - that is, they get upset that, because a combat round lasts just six seconds, and most combats are over in just a few rounds, that all of the action of the adventuring day takes place in about 15 minutes. They are interpreting "the 15-minute adventuring day" literally. I don't care about that. It makes plenty of sense to me that 15 minutes of battling magical monsters, dodging life-threatening traps, and negotiating with orcish warbands is enough for someone to want to call it a day. Adrenaline is exhausting once it wears off.
What I'm referring to (and what people usually mean when they use the phrase "15-minute adventuring day") is the tendency of players to liberally abuse D&D's resting mechanics to ensure that they have the optimal resources for every encounter - that is, the characters use all of their most powerful abilities in their very first encounter of the day, then rest as soon as possible so that they'll have those abilities back for the next encounter. Because D&D's design is predicated on the assumption that attrition is taking place, this behavior often renders the game toothless - DMs complain that player characters are too powerful, or that monsters are too weak. Maybe that's true. Or maybe we just need to stop player characters from resting so much.
Was It Always This Way?
Before I get into it, I want to take a detour to talk about older editions of D&D. Do players of OD&D, B/X, and AD&D run into problems with the 15-minute adventuring day? Maybe. One thing that has never changed is that player characters get all of their spells back when they take a long rest. So even way back in OD&D, magic-users had good reason to beg for a break after they'd burned their one spell for the day and had to resort to feebly wielding their dagger.
Throughout the editions, player characters have accumulated abilities aside from spells which recharge on a daily basis. In AD&D, paladins can lay on hands once per day, and druids can shapeshift into a either a bird, mammal, or reptile once per day each. 4e codified "daily" powers alongside "at will", "encounter", and "utility" powers. This has been further complicated in 5e by the introduction of abilities that can be used a number of times per day equal to a character's proficiency bonus, or ability score modifier, or an even more arbitrary value.
The main difference between editions when it comes to this issue is the speed of natural healing. The amount of hit points recovered after a rest has ballooned over time, and the limitations on what constitutes a rest have grown much looser. In OD&D, B/X, and AD&D 1e, characters require complete rest (i.e., no adventuring activities whatsoever) to heal naturally. In 2e, characters can heal naturally while doing light adventuring activities (i.e. traveling from place to place), but heal more quickly when resting for a full day, and never heal naturally on a day when they engage in combat.
Natural healing begins to take on super heroic qualities in 3e, in which characters can finally regain hit points at the end of a strenuous adventuring day - and not just one hit point, but a number of hit points equal to the character's level.
The super heroic trend continued with 4e, in which characters could use healing surges (equal to a quarter of their total hit points) to heal themselves at any time between combats (and sometimes mid-combat). Characters had different numbers of healing surges determined by their class, Constitution score, and other factors, with rangers, rogues, warlocks, and wizards having the smallest baseline number of surges (6) and paladins having the largest number (10). At the end of the day, an extended rest recharged all healing surges and hit points, meaning even the frailest characters had not just their usual hit points, but an additional pool of hit points equal to 150% of their maximum in nearly on-demand healing every day. The distinction between a full day of rest and a night's sleep at the end of a strenuous adventuring day - which had persisted all the way up to 3e - is lost to time at this point.
5e rolled back the extremes of 4e somewhat, replacing healing surges with hit dice. A character has hit dice equal to their level (rather than a number of surges determined by their class), the size of the dice is determined by the character's class levels (rather than being a 25% heal), and the character's Constitution modifier is added to each die. A short (1-hour) rest is required to use the hit dice (rather than being an at-will heal outside of combat). Essentially, the character has an additional pool of hit points roughly equal to 100% of their maximum (more or less, depending on how they roll) which they can use to heal in the middle of the day. Characters regain only half their expended hit dice on a long rest (compared to all expended healing surges in 4e). The healing of all lost hit points on completion of an extended/long rest survives from 4e.
The point is that the earliest editions of D&D use a different timescale of attrition. On day one of the adventure, the fighter may take only 5 points of damage, but when they rest that day, they regain no hit points. On day two, they take another 5 points of damage, and again cannot regain hit points from resting. There may be a cleric in the party aiding them with magical healing, but the point is that the damage compounds over time - no natural healing is possible so long as the fighter continues to exert their self each day. In 3e, the fighter can heal at the end of a strenuous day, but usually not completely. In 4e and 5e, the damage the fighter took on day one of the adventure no longer matters on day two, assuming that they were able to successfully rest - everything resets (except 5e's hit dice, which only reset halfway).
In other ways, the earliest editions of D&D don't rely on attrition to create challenges at all: the stench of the zombie lord kills the characters if they fail a saving throw; the touch of the wraith drains a level of experience from the affected character; rocks fall, everyone dies - no whittling away of hit points, spell slots, or per-day abilities necessary in any case.
I'm not suggesting that 5e needs slower natural healing, or to distinguish between resting at the end of an adventuring day and taking a week or more to rest completely between adventures. Instead, I hope to have demonstrated that "the adventure" (i.e., the days or weeks at a time during which the characters are adventuring, where little to no recovery is possible) has gradually transformed into "the adventuring day" (i.e., the single, brief unit of time during which the characters are adventuring, after which they recover rapidly and almost completely) - and how the adventuring day is more important to the game's assumptions of balance than ever before.
How Long is an Adventuring Day?
Well, a day is 24 hours. A long rest is 8 hours, so that leaves 16 hours of adventuring. Characters can travel 8 hours per day before needing to check for exhaustion, which leaves 8 hours for poking around dungeons or whatever. Solved.
This is wrong. For the purposes of this discussion, it doesn't really matter how long a day is. What matters is how challenging a day is. The quote from the DMG at the beginning of this post says that a "typical" adventuring day consists of "about six to eight medium or hard encounters". People get hung up on this. The more important part is this:
For each character in the party, use the Adventuring Day XP table to estimate how much XP that character is expected to earn in a day. Add together the values of all party members to get a total for the party's adventuring day. This provides a rough estimate of the adjusted XP value for encounters the party can handle before the characters will need to take a long rest.
The important thing is to determine how much challenge the party can handle before needing to take a long rest, and the challenge isn't measured in a number of encounters of X or Y difficulty, but in XP. Every encounter has an adjusted XP value determined by the number of monsters and the monsters' CR. Add up the adjusted XP value of each encounter/challenge until the party's daily XP budget is reached - that's an adventuring day. (The DM is also supposed to award XP for non-combat challenges, but assigning an XP value to these is more of a gut feeling with loose guidelines than a mathematical equation.)
Five 1st-level characters can handle 1,500 XP of challenges per day. That could be 6 medium encounters or 4 hard encounters, sure, but it could also be 12 easy encounters or 3 deadly encounters. It could be 1 easy, 2 medium, 1 hard, and 1 deadly. It could be a single encounter which is beyond "deadly" but still within the 1,500 XP budget. A common problem I see is 5e DMs planning for one "big damn encounter" per day, but still adhering to the easy/medium/hard/deadly encounter categories. Those categories are still assuming there will be multiple encounters per day! If the DM really wants to run one big damn encounter per day, they need to make that encounter much more robust, with an adjusted XP value nearly equal to the party's daily budget.
Technically, that is all true. But is it for the best? Another thing worth considering is that 5e introduces short rests. Every character gets all of their hit points and daily abilities back on a long rest, so every character is incentivized to long rest eventually. Likewise, every character can spend hit dice to heal during a short rest, but many characters benefit from short rests in ways which are unique to their class, and almost every class benefits differently, so every character is incentivized to short rest to a different extent.
On the one hand, bards, clerics, and druids, for example, regain some secondary features on a short rest: Bardic Inspiration, Channel Divinity, and Wild Shape (the primary feature of all of these classes is spellcasting, which is tied to long rests). On the other hand, fighters, monks, and warlocks regain their primary features every time they take a short rest. It's part of the balancing act between classes. Characters that recover their features on a short rest maintain their potency throughout the day - the longer the day (i.e., the more short rests they can take), the better they match up to the long rest-dependent classes. If the day is too short (especially if it consists of just one encounter), they pale in comparison, and any attempt at balance between the classes falls apart.
The 5e DMG says:
In general, over the course of a full adventuring day, the party will likely need to take two short rests, about one-third and two-thirds of the way through the day.
So if, for example, the adventuring day consists of 6 medium encounters, the party is expected to have two such encounters per short rest. Frankly, if I'm playing a fighter, monk, or warlock, I'm proposing a short rest after every encounter, so long as there isn't some time pressure. Even if I'm playing another class, so long as I get something back on a short rest, I'm taking one. It's fun to be a bard and have all of my uses of Bardic Inspiration to throw around every single encounter.
Let me just say now that I don't really do all this encounter planning and math when I'm prepping a D&D session. If I'm creating a dungeon, I'll stock it with a mixture of different types of monsters and encounter difficulties - there will be easy, medium, hard, and deadly encounters designed for a group of characters of the level I think is appropriate for the dungeon, trivial encounters designed for lower-level characters, impossible encounters designed for higher-level characters, indifferent, unfriendly, friendly, and helpful monsters in addition to hostile ones, traps of varying deadliness, and magical benefits of varying potency. I'm not making spreadsheets with XP values to plan my dungeons. It's not that deep.
Sometimes, the goal of the adventure at hand is to travel across the wilderness, find the tower where the harpies are roosting, and kill them. The characters might have a random encounter in the wilderness on the way there, but most likely, they're going to arrive with all their resources at hand. The tower won't be a complex mythic underworld with a variety of monsters, tricks, traps, treasure, and the like. The adventure will most likely big a big damn fight with a bunch of harpies, and that's okay too, so long as it's only sometimes.
The point is that characters are intended to face a certain amount of challenge (measured in XP) per day. Because some classes rely more than others on short rests to keep pace, it is better to spread the day's challenges out across multiple encounters. That being said, variety is the spice of life, and a mixture of different numbers and types of encounters per day is vital to an exciting game.
No Rest for the Wicked
The most common solution to adventuring day woes is to limit long rests in some way, forcing the characters to deal with attrition. Usually, this is done in one of two ways: either resting has to take place in a location that is some combination of safe and/or comfortable, or the "gritty realism" optional rule is used, extending the length of a short rest to 8 hours and a long rest to 7 days.
From what I can tell, Basic D&D is the only version that explicitly required resting in a particular location in order to recover resources:
Each day of rest and recuperation back "home" will regenerate 1 to 3 of his hit points for the next adventure.
One might imagine that past editions' "bed rest" rules require, well...resting in a bed, but they don't. From 2e:
If a character has complete bed-rest (doing nothing for an entire day), he can regain 3 hit points for the day. For each complete week of bed rest, the character can add any Constitution hit point bonus he might have to the base of 21 points (3 points per day) he regained during that week.
3e also defines "bed rest" as "doing nothing for an entire day". No literal bed required. Thus, I don't really think there's much precedent for forcing characters to sleep in a "safe" location (aside from the Basic D&D rule). It seems to me like a somewhat arbitrary limitation imposed by the DM to prevent resting in the dungeon. There are other ways to do that, though, which I'll get to later.
As for "gritty realism", I most often see this solution championed by true adventuring day believers who insist that it's "unrealistic" to fit that many encounters into a single day. How does one possibly solve that problem? Where might a party of adventurers face 6 to 8 encounters worth of monsters in a single day? Perhaps in some ancient complex of densely interconnected, labyrinthine rooms, where a vast array of monsters, traps, and tricks can lurk around any corner - a mythic underworld of sorts where the common sense laws of the natural world no longer apply? No, no, that simply doesn't make sense. That's not what they do on the actual plays I watch. Those people are actually playing the game, after all! How could they be doing it wrong?
Something I find interesting about "gritty realism" is this, from the DMG (page 267):
This puts the brakes on the campaign, requiring the players to carefully judge the benefits and drawbacks of combat. Characters can't afford to engage in too many battles in a row, and all adventuring requires careful planning.
This approach encourages the characters to spend time out of the dungeon. It's a good option for campaigns that emphasize intrigue, politics, and interactions among other PCs, and in which combat is rare or something to be avoided rather than rushed into.
This is not really an angle I had considered. I only ever see people discuss this optional rule as a way to fit an adventuring "day" worth of encounters more easily between long rests, not as a means to make players more carefully pick their battles, or to encourage more social interaction gameplay. It makes sense - if a combat lasts a minute but takes a week to recover from, the players may think twice before engaging, and if they're spending a week at a time in town, they may prioritize building relationships with NPCs in their home settlement.
Truthfully, aside from the atrocious name, there is a convincing case to be made for adopting the "gritty realism" rule variant. It does seem to fix a pacing problem that many people experience. I have a few quibbles with the rule and how it interacts with spell durations, preparing spells, exhaustion, and recharging magic items, but my greatest concern is that it breaks down in dungeon play.
Dungeons are still, for me, the main focus of play in 5e, and they're exactly the place where the adventuring day makes sense. It is crystal clear to me that 90% of 5e's design was done with dungeon play in mind, even if the rules do a poor job explaining that or instructing DMs in how to run dungeons. "Gritty realism" makes sense if the adventure involves a few encounters on the way to the dungeon, a few encounters in the dungeon, and a few encounters on the way back. It doesn't make sense if the dungeon is a densely-packed collection of challenges designed to test the players all on its own.
Personally, outside of dungeon play, I don't really care all that much if combat is "balanced" or challenging. The challenge of traveling from place to place isn't fighting (at least, not entirely). The journey from place to place is interesting because the characters can find unexpected things, get mixed up in unforeseen side quests and shenanigans, make new friends and enemies, and the like.
When they do end up fighting while on a journey, those encounters should be swingy. The journey to the tomb shouldn't be carefully preplanned to provide the appropriate amount of challenge for X characters of Y level. It's the wilderness - who knows what's out there? 1st-level characters can get wrecked by an ancient dragon if they're unlucky, and 20th-level characters can pick a fight with five goblins if they feel like it. The wilderness is wild. It has always been more dangerous than the dungeon.
The dungeon traditionally has levels, which correspond to the characters' levels. The dungeon is balanced - it's the site of the adventuring day. It's where the game actually works - unless the players decide to abuse rests, and thus break it. So without changing anything else about how resting works, how does one prevent this?
"YOU CAN NOT HAVE A MEANINGFUL CAMPAIGN IF STRICT TIME RECORDS ARE NOT KEPT" (AD&D 1e DMG, page 37)
Gygax comes off unnecessarily strong in the above quote, but he's not entirely wrong. I would revise the sentiment as such: "You can have a meaningful campaign without keeping strict time records, but it helps a lot to keep at least some records and solves a lot of the game's problems." Not pithy or prescriptive enough for the grognards I guess.
Some people advocate for putting every adventure on a time limit. There is an evil spellcaster in the tomb doing an evil ritual! The characters have to go through the dungeon and stop them before the ritual is complete! This happens on every adventure for some reason! This certainly works sometimes, but it's hard enough already to come up with quest hooks to propel a campaign forward. It's doubly hard to create some artificial time limit for every adventure. It also just isn't very fun for the players to never be able to slow down and simply live in the fictional world for a while.
Instead, I use wandering dungeon monsters to exert time pressure. In my games, I use a loose interpretation of AD&D's 10-minute dungeon turn concept. Here's my basic procedure for running a dungeon crawl:
- The characters enter the room. I describe it.
- Players ask clarifying questions and I answer with just enough detail to either spur the players to action or elicit more questions.
- At least one player says they want to do something.
- I ask every other player what their character is doing (even if it's "Just standing around" or "Waiting for so and so to do their thing").
- I give each player new information based on what they're doing, call for ability checks, etc.
- Repeat.
A 10-minute dungeon turn is when all of the characters are doing their chosen thing in that room. If the fighter is muscling open a sarcophagus, the wizard is studying a tome, the cleric is examining an altar, and the rogue is checking for traps, that all takes the same 10 minutes. Every turn, I make a wandering monster check, with a 10% chance of an encounter. On average, the characters can do ten things before they encounter a wandering monster.
This accomplishes two things: It puts time pressure on the players without needing to make every adventure a "stop the ritual" quest, and it also obviates the need to put arbitrary limits on resting in the dungeon. A short rest is 1 hour, which is six wandering monster checks. The characters have a decent chance of squeezing that rest in without having an encounter (I am considering changing short rests to 10 minutes, just to really juice those fighters, monks, and warlocks a bit). A long rest is 8 hours (and because of the one-long-rest-per-24-hours rule, the characters may need to wait around for a bit before they can actually start the rest). That is, at minimum, 48 wandering monster checks. Long resting inside the dungeon is an exercise in frustration, at best.
By comparison, in the wilderness, encounter checks are made every four hours, so resting outside the dungeon is a much safer bet. Okay, so the characters just leave the dungeon to rest after every fight. The problem is still there.
I fixed this by checking for wandering monsters every time the characters reenter a room they've already been through. If the characters have to backtrack through ten rooms to leave the dungeon, they will probably have an encounter on their way out. Then, they will probably have another on their way back in. I justify this by telling myself that monsters are more likely to be patrolling areas where the party has already caused a ruckus or are known to be using for ingress and egress. It also rewards the players for finding additional entrances and exits to/from the dungeon which allow them to go in and out without passing through as many rooms.
I've gone back and forth on whether or not wandering monsters should be drawn from the dungeon's key or should materialize out of thin air. I am inclined towards the latter because if wandering monsters are taken from the key, it actually becomes beneficial to run into them. If there are 20 goblins in one room, and the party randomly encounters half of them wandering the dungeon, they've now split the single difficult encounter into two easier ones purely by chance, due to a mechanic that is intended to be a disincentive.
I like wandering monsters that materialize from the dungeon itself because I like a mythic, otherworldly dungeon. I like to fill my dungeons with supernatural creatures like elementals, fiends, oozes, and undead - monsters that be conjured, seep through cracks in the floor, or manifest from the shadows themselves. I don't really have to justify it because the characters haven't explored the whole dungeon yet - the players don't know what's all in it, so they have no way of knowing where the monsters are coming from. If a specific type of monster has a lair in the dungeon, I'll cross them off the wandering monster table once they've been defeated in their lair, allowing player characters to eliminate threats as they progress.
Okay, so the characters fought through ten rooms in the dungeon. Let's say two rooms had preplanned encounters (medium and deadly), and the characters encountered a wandering monster while exploring (hard). They decide to rest, and leave the dungeon the way they came, having another encounter (medium) on their way out. Assuming they are our aforementioned 5 1st-level characters with a daily budget of 1,500 XP, that gets us to 1,375 XP (250 x 2 = 500, + 375 + 500 = 1,375). Not 1,500, but very close - some delves will be easier and some will be harder (and remember, not all of the encounters will be with hostile monsters, and characters have abilities which allow them to avoid combat with hostile monsters, so players can still pick and choose their fights, and often expend resources when doing so).
While They're Sleeping
The characters have made it out of the dungeon and get to rest. They might have two to four wilderness encounter checks while making camp and resting - depending on the terrain, they will have fewer or more checks with a lesser or greater chance of having an encounter. They go back into the dungeon the way they went the previous day and maybe have one wandering encounter. So what? They cleared out a bunch of rooms the day before. The dungeon is easier now.
But it isn't, necessarily, because the dungeon and its denizens do things while the characters are away. There's plenty of commentary and differing philosophies about restocking dungeons. Generally, it's most common in old school play, where dungeons are tentpole megaplexes intended to support entire campaigns on their own. However, I've found that restocking works plenty well in 5e and with smaller dungeons.
Now, restocking makes a lot more sense in editions of D&D where natural healing occurs much more slowly. If the characters spend a week recovering in town, it's understandable that the dungeon would change - if they spend just a day camping directly outside, not so much. This is another decent argument for the "gritty realism" rest variant, but again, I like my dungeons to be filled with supernatural creatures that can magically materialize at a moment's notice, so the sudden repopulation of monsters doesn't bother me.
I already linked some pretty well-considered ways of restocking, but I like to keep it simple - basically, every room the characters have "cleared" has a 10% chance of being restocked, usually with monsters, but sometimes with traps (it is almost always something bad, because the point is to introduce some new challenge into the cleared space, unless the characters have allowed some friendly faction to move in). The new monsters are drawn from the wandering monster table, excluding those monsters whose lair within the dungeon has already been cleared.
Using the aforementioned example of ten cleared rooms, on average, one would be repopulated. The characters are still making progress through the dungeon, but now on their way back in, they are probably dealing with one wandering monster and one restocked room. Then, they still have to deal with the rest of the dungeon, which they haven't touched yet.
There are also more common sense ways of restocking - if the remaining monsters are aware of the characters' initial foray, they may move around to different areas, set traps, make common cause with other monsters, and the like. I like to be surprised as a DM, so I randomize all of this and try to create a fictional justification for it after the fact.
I personally prefer not to award XP for defeating wandering monsters and restocked monsters, because both are intended to be avoided. Between wandering monsters, restocked rooms, the time-consuming nature of combat in D&D, and little to no XP being gained, this probably sounds like unnecessary cruelty and a big hassle for the players, and in a way, it is.
By encountering these monsters, the players have already failed at the challenge, which was to use their time efficiently and avoid doing extra work. If the players are getting unlucky on the die rolls and end up dealing with a bunch of extra encounters, I might throw them a bone, but the bulk of XP is for clearing the dungeon, not clearing it again because they didn't go far enough the first time. I'm always very clear with the players: "This is when I'm checking for wandering monsters" and "If you want to leave, you might want to try to find a shortcut out first" and "If you leave now and rest, there might be more monsters when you come back".
The trick is this: if I want to (and I don't always want to), I can decide how many "days" I want the characters to have to spend in the dungeon before "clearing" it. If it's meant to be a small dungeon, it will probably have an adventuring day's worth of challenges. If it's a three-level dungeon, it will probably have three adventuring days' worth of challenges (one per level).
The point is for the characters to push themselves, and for the players to feel motivated to get a full "day" in. After they "clear" a level, maybe that level is safe enough to rest on, and won't be restocked. I'll say "Hey, you cleared this area. It's safe if you want to rest before pushing on." The players are rewarded for actually pushing themselves to complete a full day of adventuring, and for clearing the dungeon efficiently. If they dilly dally too long or backtrack for breaks too often, they're only hurting themselves by having unnecessary encounters.
Again, I don't always abide by this by-the-numbers, balancing act approach to adventure design, but I do think it's helpful to understand the concept of challenge by attrition and the unit of measure that is the adventuring day. A little time pressure goes a long way towards pushing the players to play the game the way it was designed, and it turns out that when they play it that way, it works pretty well.