Afraid of losing all those hard-earned frequent flyer miles? Please refer to the following cheat sheet for mileage policies listed by airline:

Remember, even if you have no plans to travel, you can preserve your miles by making an inexpensive purchase online. Generally, these online shopping partners offer at least one mile per dollar spent, but sometimes they award 10 miles or more. And if you use your airline affiliated credit card, you get an extra mile, but the credit card miles pale in comparison to the shopping miles you can earn. 

Scores of well known retailers participate in these airline malls, including Brooks Brothers, Circuit City, The Container Store, Dell Computer, Drugstore.com, Sears, Target, and Walmart, to name but a few. See our guide to preserving miles.