[Xhad]

If a pot is five or six handed, at least some of the limpers will be in there with trash; there is no reason to assume everyone or even most of them are in there with real hands. If it's bet and raised before it gets to you, or if your pair outs complete straights or flushes, or if the better is a weak-tight player that won't bet without at least top pair, go ahead and discount your outs, but to do so otherwise is incredibly weak-tight. Also, a lot of these same bad players will automatically limp for one bet, and automatically call one bet on the flop, but fold their weaker draws for one cold raise on the flop if they miss.

If your opponents really are always calling, then raising with overcards is usually a bad idea. But if someone who will bet any piece of the board (and then call down a raise) bets into you and a raise might get the pot heads-up or three-handed at most, then a raise is mandatory if you have at least overcards with some kind of draw (even one as weak as a backdoor flush off a king), or middle pair since the bettor is betting a lot of hands you can beat, there's no reason to assume anyone else has anything, and if the bettor is really passive you may be able to just check it all the way to showdown if you want.

This brings up another point about late position: the free card works more in these games than it does in a more normal game. When you have a gutshot to the nuts and overcards, and the pot is 12 bets, and your opponents will almost always check to you on the turn if you raise, then you should raise whether it will fold anyone or not.