I happened to open the hood while my car was warming up a couple days ago, and I noticed a small piece of the belt flapping.
I just got it replaced about 6 months ago. I stopped the car and took some pics. The edge is fraying, and there'* a foot long section of the belt that is missing a groove. Nothing serious. The car still drives fine, the belt is tight, the pulleys are lined up... I think the belt is good for a while.
But I'm taking it in to the shop in the morning after confronting them about it Monday. I'm almost positive they gave me a crappy belt or installed it incorrectly. But they said they'd look at it. Which probably means they'll look at it for a 1/2 hour and say it wasn't their fault, and pretend the idler pulley or something else is causing it. I have a bad feeling that is exactly what will happen. I want them to replace it for free!
We'll see what happens.