I know it's common to tip person's in the service industry, like 15% for restaurants, 20% if service is exceptional.
But what about hotels? Do you leave a tip every morning or at the end of your stay? How much do you commonly leave?
How about hotel valet? If they charge you $28 to valet you car for one night, do you still tip? how much would you?
I don't mind tipping, I have worked in the service industry, but where is the line drawn for over tipping?