Unfortunately, there isn't a set rule that works globally. But if you're dissatisfied with any service performed in any country--from wait staff to housekeeping--don't tip! Tipping is a reward, not an obligation. That said, in countries like Japan, it may be considered insulting to tip. Do your research before you go. One great resource is the "Worldwide Tipping Guide" on magellans.com. It outlines appropriate tips for service people around the globe.

A travel writer extraordinaire, Michele Sponagle has visited more than 40 countries around the world. Click here to send her your questions.