From No Limit Hold 'em: Theory and Practice by Sklansky and Miller.
Concept No. 6: It can be right to call with decent hands that have little chance of improving even if you plan to fold if there is a bet on the next round.
I like this one. It's not groundbreaking, and it should be pretty obvious, but it's common for experienced players to give the opposite advice: don't call a bet on the turn if you can't face another bet on the river.
Well, often enough, that river bet never materializes after you call on the turn. As S+M say, "there are plenty of reasons to bet the flop, but check the turn if called (or to bet the turn, but check the river if called). You'll do it, and so will your opponents." I agree.
Again, this seems pretty straightforward, but I'll go through the basic idea. Many players who bluff on the turn and get called will expect you to follow the conventional wisdom and call any river bet as well. Naturally, these players will often give up the bluff and just check on the river, since they figure any further bluffs will be called. This means that if they do bet again on the river, they will have a stronger range of hands. This necessitates a stronger calling range on your part. That is, you'll have to fold some of the decent hands that you called with on the turn.
Sometimes I find myself in a game where I get called a lot pre-flop, but then my opponents tend to give up easily on the flop. I think they often have decent hands on the flop, but they don't want to face another bet on the turn, so they figure they should fold right away. By folding too early, though, they make it far too easy for me to win these small pots.