Here's my rules: 1) I tip the van driver if he's there on time, or within 5 minutes. 2) He has to LOAD and unload my bags. 3) If we wait more than 5 minutes for another inbound crew, no tip. 4) If I'm riding with 17 people in a 15 passenger van, no tip.

As far as restaurants go, I always tip unless the service is incredibly poor. If the waiter makes an effort at his job I tip 15%. If they really go above and beyond, make that 20%. Crappy service usually garners a 5% tip.

Also, and this is going to make me look like a tightwad, I base the tip on the cost of the meal excluding sales tax.