It begins with surprisingly slow movement rates. Assuming that at least some characters were wearing heavy armor, a party of dungeoneers could explore just 60 feet of tunnel in a 10-minute turn. That seems painfully turtlelike, but as the rules explained, it assumed characters were mapping carefully, trying to be quiet, listening at doors and junctions, and searching for traps and secret doors as they went. They could move faster if they wanted to but only at the expense of stealth and caution. Additional searching, such as tossing a chamber for valuables, was another 10 minutes at least, or more if it was a big room.
Barrowmaze by Greg Gillespie). It shows the first portion of the dungeon that characters enter. Just mapping it -- that is, walking through the corridors along the path shown and looking into but not actually entering most of the rooms -- takes about an hour and a half of game time at 60 feet per ten minutes. Every fight that breaks out adds 10 minutes (extra time beyond actual combat is spent binding wounds, cleaning weapons, looting the dead, and so on). Fighting everything in this section of the dungeon, as characters are likely to do, adds another 80 minutes. Searching a room adds another ten, so fully searching all 24 rooms keeps everyone busy for an additional four hours.
That’s seven hours of in-game exploration and combat.
It's unlikely that a low-level party can handle all of this in one go. They'll run low on hit points and spells after two or three fights. When that happens, they will need to retreat and rest for the night.
During those seven hours of exploring, searching, and fighting, the DM would also make 30 or more rolls for wandering monsters. Those are likely to trigger four to six more encounters. Wandering monsters are a real headache for dungeon explorers. They deplete your precious combat spells and hit points for very little gain, so you want to minimize them as much as possible. But wandering monster rolls are literally as constant as a ticking clock. As long as you're in the dungeon, those rolls keep happening, and the more carefully you move and search, the longer you’re in the dungeon.
Hanging over all of this is knowing that leaving the dungeon can cost you most of the gains made today. When adventurers retreat, monsters move back in. At least some of the chambers that were fought over today will need to be retaken tomorrow from the monsters that reoccupied them overnight. Since the valuable treasure was hauled away yesterday, those fights spill your blood for little gain.
In short, a group of explorers needs to deal with these conflicts.
- To map accurately and protect yourself against ambushes and other nasty surprises, you need to move slowly.
- To minimize danger from random encounters and get the most from your long-duration utility spells such as find traps and detect magic, you need to move quickly.
- To cement your gains, you need to press on for as long as possible before retreating for the day.
- To get out alive, you need to head home before you're so spent that bumping into a wandering monster on the hike back to the exit will end in a TPK.
I decided to actually check on my memory; here are the numbers as I looked them up. The base assumption is a six-member party advancing at the speed of its slowest member, which typically is a dwarf in heavy armor. Only B/X rolls moving and searching into a single number. All the other rules make you ante up time for searching separate from movement, which complicates the math a bit. It would be nice if they all just assumed you tap on the walls and prod the floor with a pole as you go.
|OD&D||37.5 feet/10 minutes|
|1st Edition AD&D||50 feet/10 minutes|
|1981 Basic/Expert||60 feet/10 minutes|
|2nd Edition AD&D||55 feet/10 minutes|
|3rd Edition D&D||50 feet/10 minutes|
|Pathfinder*||1,000 feet/10 minutes|
|4th Edition D&D**||900 feet/10 minutes|
* I don't have high confidence in this seemingly outrageous number, since I don't get to play much Pathfinder. The rules don't address the issue specifically. Using the Perception skill takes a move action, so searching as you go would seem to cut your speed in half. That's the number I used. You could easily argue it should be half this, on the assumption that there's a lot of broken and rough terrain in a dungeon.
** Another case where the number seems ridiculously high in comparison with the others, possibly because the rules don't really address the issue. A lot of assumptions are involved. It's entirely possible that this number is low by half.
I'd welcome anyone doing their own analysis and providing alternative numbers, either to agree or disagree with mine.