My basic principle, the one underlying everything else that I'm going to talk about, is that restocking a dungeon should be less complicated than simply coming up with an entirely new dungeon or dungeon zone. This seems obvious, but I've seen some fairly complicated systems out there that violate this principle, and I wonder how much they end up using the system in play, rather than just sort of presenting it as a thought exercise on a blog.
The first question I think people should ask themselves is whether they even need to restock the dungeon? I'd add the following consideration: Why restock instead of pushing PCs to new dungeons or new zones within the dungeon? Restocking encourages PCs to linger in zones nearer to the entrances to the dungeon, it slows down their progression through the dungeon, and it can make it seem like their efforts to clear out the dungeon are pointless.
If you don't have clear ideas about how manage these things so they don't kill the fun, I'd actually recommend against restocking. Instead, I'd recommend that you present clear diegetic signs to indicate that a dungeon or dungeon zone is empty / deactivated / cleared and should be traversed to get to new material instead of lingered in. These signs should be some combination of boring and dangerous, with the emphasis on boring instead of dangerous, since this is less likely to confuse them into thinking that there are still monsters and treasure to be found here.
Dungeons that do the best with being restocked are ones that allow or incorporate ways of overcoming the slow down in progression through them caused by restocking. This includes dungeons with short-cuts in them that have to be discovered or created during play (including multiple entrances or teleporters); dungeons with organised factions that you can negotiate with for safe passage; dungeons where you can change the overall organisation of the level (e.g. draining or flooding it) to reach new parts of it; and dungeons where you can temporarily delay or "turn off" the restocking (perhaps by shattering an evil altar or something that draws monsters to it).
Restocking at its best incorporates and recombines familiar elements of the dungeon or dungeon zone, but does so in a way that produces emergent and unpredictable results. One interesting (and perhaps unexpected) thing I've discovered over the years is that PCs tend to feel that their actions have had the most impact on a dungeon or dungeon zone when it shifts levels of organisation. That is, when they "clear" a dungeon that's filled with highly organised enemies and the next time it goes through, the enemies are comparatively disorganised, or when they clear a dungeon of a bunch of random monsters, and then the next time they come through, they find a highly organised set of foes has moved in to replace them.
What Should Trigger Restocking?
I use four different triggers to determine when to restock via the method I'll describe below. I don't have a strong preference for one over the others, so I just rely on discretion and what I think will generate the most interesting results. These are ranked in rough priority.
1) After the PCs kill the two most powerful monsters or groups of monsters on the level
2) After the PCs have explored all non-hidden rooms on the level
3) Every 2d6 expeditions
4) When the PCs go into extended downtime away from the dungeon
I use these because I like exploration, and hate mop-up. I use the dice counter method mainly once they've cleared out an area entirely and keep on passing through it, and I use the downtime method as a backstop just in case they take an extended break from an area. If you do use a dice counter, I recommend using something that's guaranteed to give you at least a few sessions to restock, instead of trying to do it for every session.
I use four different triggers to determine when to restock via the method I'll describe below. I don't have a strong preference for one over the others, so I just rely on discretion and what I think will generate the most interesting results. These are ranked in rough priority.
1) After the PCs kill the two most powerful monsters or groups of monsters on the level
2) After the PCs have explored all non-hidden rooms on the level
3) Every 2d6 expeditions
4) When the PCs go into extended downtime away from the dungeon
I use these because I like exploration, and hate mop-up. I use the dice counter method mainly once they've cleared out an area entirely and keep on passing through it, and I use the downtime method as a backstop just in case they take an extended break from an area. If you do use a dice counter, I recommend using something that's guaranteed to give you at least a few sessions to restock, instead of trying to do it for every session.
The Actual Method
Here's the method I actually use for restocking, based on the above considerations. You will need:
1) A wandering monster table
2) A wandering trap table
Here's the method I actually use for restocking, based on the above considerations. You will need:
1) A wandering monster table
2) A wandering trap table
3) A "theme" table of varying length (I usually use six to ten entries) whose creation I will describe below
All you do is roll on the theme table, then roll on the wandering monster table and wandering trap table for each room (in whatever order you please). Any entry on either table that's transient on the table leaves the room empty (from the perspective of a room's contents monsters, traps, treasure, etc.). If it's not a transient entry, then put it in the room. As you roll, apply the transformation rules from the theme table (more on that in a moment) to alter the results. Generate treasure for the lairs as appropriate. At that point, you're ready to go.
NB: I recommend you do this for every room in the area, even if the PCs didn't clear it out the first time.
The Theme Table
I call it a "theme table", but only because that's quicker and easier to write and say than "a table of rules of transformations". Each entry should be a few global rules that modify how you use the wandering monster and trap tables to create entries.
I usually start these off as a 1d6 table and expand them as I get good ideas to fill out more entries.
Here's a sample of one to give you an idea of what I'm talking about:
All you do is roll on the theme table, then roll on the wandering monster table and wandering trap table for each room (in whatever order you please). Any entry on either table that's transient on the table leaves the room empty (from the perspective of a room's contents monsters, traps, treasure, etc.). If it's not a transient entry, then put it in the room. As you roll, apply the transformation rules from the theme table (more on that in a moment) to alter the results. Generate treasure for the lairs as appropriate. At that point, you're ready to go.
NB: I recommend you do this for every room in the area, even if the PCs didn't clear it out the first time.
The Theme Table
I call it a "theme table", but only because that's quicker and easier to write and say than "a table of rules of transformations". Each entry should be a few global rules that modify how you use the wandering monster and trap tables to create entries.
I usually start these off as a 1d6 table and expand them as I get good ideas to fill out more entries.
Here's a sample of one to give you an idea of what I'm talking about:
1) Monsters from elsewhere have moved in and taken over. Use the wandering monster table from an adjacent zone (or the overland table if there are no adjacent zones) to populate the rooms.
2) The two most intelligent monsters generated are the leaders of factions that are at war with one another. Reroll on the wandering monster table for all rooms and corridors adjacent to the room each one is in (even if there are already monster results for these rooms). These are their allies and servants.
3) All monsters in this area are mind-controlled by the first monster you roll a lair result for. If no lairs are generated, then roll again for each room on the wandering monster table and add additional monsters until you get a lair result.
4) Monsters are using traps to drive intruders out. After the first monster is placed, all further monster results are actually rolls on the trap table (that is, roll twice for traps for each room).
5) Monsters are reworking the architecture of the area. Any two rooms with the same monster type in them will have a secret passage connecting them. If any monster type has a lair on this level, then there will be a secret passage connecting them to any other rooms containing the same monster type.
6) There is a power struggle going on for control of this area. After rolling for monsters for each room, reroll for each room a second time using a wandering monster table for the nearest adjacent zone. Monsters from different wandering monster tables are hostile to one another.
These are all fairly straightforward and rudimentary. You could easily expand this (I both do so in practice and encourage you to do so). In its current form, it's highly generic and could be used for any dungeon, and on any level of that dungeon. The table is meant to be used multiple times for the same area, and each time different "layers" of results build up.
If you really wanted to, you create a unique table for each zone of the dungeon. I recommend against this (based on the above-mentioned principle of keeping restocking simple), except if the level has a very strong theme (e.g. it's a rotating level, or a level that floods and drains or something else like that). In that case, I'd use a d4 table with four strong and interesting options customised for that level, and otherwise use the generic table for the rest of the dungeon.
My experience using various versions of this method is that it's easy to use, fairly fast to do, and the addition of the themes / transformations is more than enough to make it seem like complex and interesting changes are going on in the dungeon in response to PC actions, without having to get into a lot of political simulation, or relationship mapping or weird flowchart things or other overly complicated stuff.
2) The two most intelligent monsters generated are the leaders of factions that are at war with one another. Reroll on the wandering monster table for all rooms and corridors adjacent to the room each one is in (even if there are already monster results for these rooms). These are their allies and servants.
3) All monsters in this area are mind-controlled by the first monster you roll a lair result for. If no lairs are generated, then roll again for each room on the wandering monster table and add additional monsters until you get a lair result.
4) Monsters are using traps to drive intruders out. After the first monster is placed, all further monster results are actually rolls on the trap table (that is, roll twice for traps for each room).
5) Monsters are reworking the architecture of the area. Any two rooms with the same monster type in them will have a secret passage connecting them. If any monster type has a lair on this level, then there will be a secret passage connecting them to any other rooms containing the same monster type.
6) There is a power struggle going on for control of this area. After rolling for monsters for each room, reroll for each room a second time using a wandering monster table for the nearest adjacent zone. Monsters from different wandering monster tables are hostile to one another.
These are all fairly straightforward and rudimentary. You could easily expand this (I both do so in practice and encourage you to do so). In its current form, it's highly generic and could be used for any dungeon, and on any level of that dungeon. The table is meant to be used multiple times for the same area, and each time different "layers" of results build up.
If you really wanted to, you create a unique table for each zone of the dungeon. I recommend against this (based on the above-mentioned principle of keeping restocking simple), except if the level has a very strong theme (e.g. it's a rotating level, or a level that floods and drains or something else like that). In that case, I'd use a d4 table with four strong and interesting options customised for that level, and otherwise use the generic table for the rest of the dungeon.
My experience using various versions of this method is that it's easy to use, fairly fast to do, and the addition of the themes / transformations is more than enough to make it seem like complex and interesting changes are going on in the dungeon in response to PC actions, without having to get into a lot of political simulation, or relationship mapping or weird flowchart things or other overly complicated stuff.
