Belt like noise?

[g8r]

The X is making a belt like squeal but very low in volume consistent with the rpm. Thing is, the belt is fairly new. Could it be anything else? How long do belts last?

 

[MyExpWork]

Could be the idler pully.

Mine makes noise upon 1st startup in the morning, but my serp belt is pretty new.

 

[spta97]

Mine was the belt tensioner. I had it replaced (along with the belt) but it still makes noise when it is wet / humid out for about 3 seconds.