f you do a timing belt service you must consider replacing the pivot arm bushings too. Especially if you feel some play that mat cause the belt to change its path along the cam wheels. Serious wear on the sides on the belt may be caused by the belt not running the correct path and hitting the arm or any other metal part. You will see debris from abrasion under the belt cover. Obviously running noises might point to the potential problem too.

I'd have to look if I have a special note on that pivot arm part, but a quick answer: look in PET part number 928.105.613.04 in illustration 103-10. You see two of those where the arm pivots. If there is too much play the belt will change path and things may wear quickly or the belt may even run off.
1992 928gts Midnight Blue
The Netherlands