Or anything else need to be replaced as well?
When replacing alternator does the serpentine belt need to be replaced also? on 2002 Saturn SL1
If its worn or has cracks in the ribs it would be a good time to replace but if its not very old and still looks to be in good shape reuse it. Inspect belt tensoiner and all idler pulleys for loosness or noisey bearings before you put the belt back on.