serpentine wears out fast

i have had the 2004 alero for a year and half and put three belts on.....the belts start the chirp early on then eventually squeal constant non stop.....i have checked the idler pulleys with a stethoscope and no grinding....alternator is free so is tensioner i have replaced water pump as i thought that was problem as there was slight play....i dont know what else to look at??? any help would be great thanks

Is this a 3400 or a 2200?

Look for fluids getting onto the belt causing it to slip. Also work the tensioner back and forth and make sure that it moves only laterally, and not in and out when you move it back and forth.

I did check for fluid and can't find any although I do not have a good view of the crank I had alreadyt worked the tensioner and it is fine and it is a 3400