"Men are even easier," she says. "They can wear the same thing and same shoes every day, and nobody will notice."

Packing Tips and Rules

Here are Annabel Cohen's 10 rules of packing:

1. Bring only dark clothes that can be worn together.

2. Take one nice thing to dress up the dark clothes, such as a great necklace, tie, scarf, or shoes.

3. Bring only three pairs of shoes and wear the heaviest pair on the plane, along with your heaviest clothes.

4. Bring clothes you can part with, so you can discard them along the way if you need to.

5. Bring only an ultralight computer, such as the MacBook Air.

6. Use plastic food-stor- age bags to pack not just toiletries but also under- wear, batteries, matches.

7. Leave hardcover books, shampoo, and hair dryer at home.

8. Limit gifts you buy. Most people back home don't really need a gift.

9. Blog from your trip.

10. Bring a small U.S. map to show people where you live.

Carry-on rules

A carry-on is useless if your bag won't fit into the overhead compartment. So follow these rules:

1. Buy a light suitcase. For one with wheels, look for one 7 to 9 pounds and no taller than 21 inches. For a carry-on bag without wheels, try the Rick Steves convertible carry-on

(3 pounds, $99.95, www.ricksteves.com).

2. Measure your suitcase. Most airlines allow 45 inches (length plus height plus width). That usually means a bag no more than 21 by 14 by 10 inches.

3. Do not unzip the "expander" on your bag unless you plan to check it. It will be too fat to fit into the overhead.