According to Cook's Illustrated, Sep/Oct issue 2010:

In the test kitchen, these pans barely last six months. And even if you use your nonstick pan only a couple of times a week, the Cookware Manufacturers Association concedes it isn't built for the long term: "If you get a year to a year and a half of life out of [a new nonstick pan], we think you got a pretty good deal," says Hugh Rushing, executive vice president of the association.

I had no idea they were supposed to not last any longer.