Know the rules and limits for carry-on bags

This warning is especially important if you are traveling overseas, where baggage limits can be much stricter. Happily, Web luggage retailer ebags.com has a useful section with the carry-on requirements of many major airlines and even recommends which bag to buy for the airline you plan to fly. Also, Seat Guru has a very thorough list of all the baggage rules for every major and minor airline around the world (click on the airline's name, then click on the "baggage" tab).