Get excited when you see that you've earned a few more frequent-flyer miles? You're not the only one. An estimated 320 million people all over the world were trying to collect miles in 2012. In 1999, Business Week called them the "second currency" of the US. However, it's not necessarily easy to redeem those miles and they may be worth less than you think. As Gerchick explains, the airlines have released more miles, enough so that mileage expert Tim Winship says that, in money terms, the value of a frequent flyer mile has dropped from 2 cents to 1.2 cents.
