Wandering Monsters

I was just thinking about the philosophy of Wandering Monsters.  It's interesting that indoors and outdoors they serve opposite purposes in some ways.   In a dungeon, the wandering monster check exists as a balance against players wasting in-game time.  If not for wandering monster checks, then the players could just enter each room, and  say "we're staying here checking everything until all secret doors are found, all treasure discovered and until we bust open every chest."  With wandering monsters, players have to balance the risk of the monsters showing up with the possible rewards of taking a long time to search.  Wandering Monster checks also give some purpose to picking locks, knock spells etc, ways of opening doors and chests without bashing them with large hammers, since the bashing raises a racket and a monster check.

With Old School versions of D&D (basic, original, AD&D1), most experience points come from treasure, and monster experience is less important (especially at low levels).  Wandering Monsters in dungeons are usually lacking in treasure.  Therefore, wandering monsters are a drain on resources without any real reward and so are something that the players should be eager to avoid.  There existence forces the players to make choices about actions, and balance consequences, and I think that is a key to a good game session.

Using the game trappings of "turns" and a standard check roll and pre-made table, makes the monsters easier to take than if the DM were just to throw a "grudge monster" when he thought the players were wasting time.  I find the general scheme of a "objective" structure to be the best tool for running a game where the players don't feel like tools.

In wilderness travel, wandering monsters serve a different purpose.   They often have treasure with them and so can be actively sought by the players.   What they really exist to do is to slow down the real-world time spent in overland travel.   The existence of the wandering monster check makes overland travel a serious choice to be made.  It makes the world more vivid.   If the players take advantage of them, the wilderness wandering monster checks can be complete adventures in and of themselves.

Games like Savage Worlds and D&D4e, combats are longer to run and more involved to set up and to run out.  The real time length of running the encounters is a bit too much to justify the encounters.  I noticed in the Slipstream campaign that while we were supposed to run random encounters for space travel, and I tried to do it in the sessions I ran, it was an overwhelming time suck.  I ended up giving the crew a special high-speed engine just to cut down the number of encounter checks.   So, in many ways the uses of the wandering monster depends on quick and easy encounter resolution.