Why adventuring parties?

[Michael Thayne]

In Dungeons and Dragons, PCs usually don't need to be persuaded not to take all of their 1st-level warrior followers into the dungeon with them. PC and monster power grows more or less exponentially with level. Even at mid levels, area effect attacks, immunity to non-magical weapons, and similar monster abilities tend to make those 1st-level warriors next to useless. In Dungeon Fantasy Roleplaying Game, on the other hand, the gap between highly skilled characters and average folks is not quite as great. This can raise questions of why quest-givers even think to hire groups of 4 to 6 PCs when you can send a small army of men with crossbows and halberds.

I Smell a Rat actually does a pretty good job with this. The quest-giver (Lee) wants the job handled discreetly, and if the party relies on buffs to get past the rune-lined hallway, buffing an army of spear-carriers is out of the question. Those tricks could be recycled a few times, but eventually they'd get old. A few monsters are tough enough to make spear-carriers mostly useless, though those monsters are rare. Few monsters have DR high enough to protect against bodkin points, and Diffuse monsters often have crummy attacks to the point of not being obviously more dangerous than a simple orc. Supernatural Durability maybe does the trick, especially when the spear-carriers witness the thing shrugging off impaling by a spear and they all run away.

So I feel like I'm coming up short in terms of explaining why small groups of four to six PCs can regularly get work that doesn't involve working with an army of lower-ranking fighters. Does anyone have some favorite tricks they'd like to share?