I have an HTC Hero (Droid) that began restarting itself, shutting down, generally not working. Sprint tried to reset it, but that didn't work. I was still about 8 months from being able to upgrade, and I hadn't gotten the insurance they try to sell you, so I figured I was screwed and would have to pony up for a new phone at full price (and yes, I need a smart phone for work). Sprint was great. They ordered a replacement overnight and only charged me $35. Pleasantly surprised.