Tipping is about the most confusing — and for some, infuriating — part of traveling. It can start to seem that handing out tips left and right will be the thing that breaks your bank account, so before you start overtipping, you should know who gets tipped, who doesn't, and how much is enough.

First, though, let's talk about tipping as a general practice. You aren't imagining things — more and more people out there in the service industries expect to be rewarded for doing jobs that don't seem to require a whole lot of service beyond what they're being paid to do (say, handing you the $5 cup of coffee that you ordered).

This book will advise you to definitely dole out the tips, but to do so wisely. The bellboy who hauled your eight heavy suitcases into your hotel room with a smile on his face has earned a tip; the girl in the ice cream parlor who scooped up your cone without ever making eye contact with you probably hasn't.

If you're the most generous person on the face of the earth, feel free to tip everyone. If you're like the rest of us, you have to draw the line somewhere. Save your tipping for the people who are actually working hard to serve you, such as:

• Hotel maids: Leave a couple of dollars out for your maid each day (because you may not have the same one twice) and put it on a piece of paper marked, “For the maid.” Maids are instructed not to take cash that isn't clearly marked as theirs.

• Waiters/waitresses: For a job well done, tip 20 percent of your final bill.

• Bellboys: $2 per bag and for each hospitable gesture he performs (turning on the TV; flicking on the stereo, and so on).

• Valets: Give the guy $2–$3 (more if he had to run a mile in the snow to get your car).

• Doormen: They don't get a tip every time they open the door for you. (Phew!) If he hails you a cab, give him a few bucks ($2–$3 is plenty). If he helps you with some of your heavy suitcases or packages, give him $1 per bag; add a little more if he carries them to your room.

• Concierge: If he helps you make reservations or secures tickets for a show for you, $5–$10.

• Cab drivers: 15 percent of the total fare.

• Skycaps: $1–$2 a bag.

Be aware that if you order room service, a 15 percent gratuity is often automatically added to the bill; the same is true of restaurants in many foreign countries, so always read the fine print on the bottom of the bill!