Ahh...the airfare juggle. Airfares change like the wind. If you're looking at Southwest, I would book without hesitation because you can get a refund (in the form of a credit if the original price is non-refundable, which all the low fares are). You can use the credit yourself or give it to anyone you choose to use within 1 year. Southwest is by far the most liberal airline regarding use of credits. Most other airlines will also offer credits on non-refundable fares if you find the fare you paid goes down before you fly, but the restrictions are tighter. I usually have a threshold that I look for before I book, e.g., if I can get my flight for under $200 pp/ round trip, I automatically book it. I book SW as early as possible (as another poster suggested) because they pretty much sell out. Airlines aren't like cruises in that earlier booking doesn't always equal lowest fares, but on the flip side, you run the risk of the flight you want becoming completely sold out if you wait too long to book. If you're online regularly, check with your specific airline website for pricing. Southwest, for example, doesn't appear on Travelocity, Orbitz etc. and they offer their best deals directly on their own web site. I've found many carriers are beginning to catch on and are doing the same thing. I regularly book airfare for my company as well as my family, and it's a crazy game to play!