I agree with Glenn. It depends on your taste. I would recommend that you start out with light amounts and keep trying more until you reach what you like. It's easy to overdo it.
Also, different woods will act differently on different meats. For instance, I go 5 or 6 pieces of apple for pork butts, 5 or 6 cherry for brisket, 2 or 3 apple for ribs, 2 or 3 hickory (sometimes with some sugar maple) for chicken.
I never ever use mesquite.
Russ