serpentine belt tensioner pulley

[RSG]

So...we have these items mentioned in this posting:
1. Tensioner
2. Idler
3. bearing pulley

Which do you suggest to replace at say, 100k?? My belt is looking like it wants to shed some winter fur. The top pulley next to the alternator has black gunk stuck to it. I hear a squeak somewhere. Thanks!

 

[BJS]

all of the above.

You can do the pulley bearings for the idlers if the pulley is still in good shape... more work, less $$$, more hassle @ the parts store.