A camera with a shutter that buzzes anemically like a dying bee would benefit from a CLA.
If it fails to open the film gate at top shutter speeds.
If you can't see through the viewfinder.
If you feel like you are pulling teeth when winding.
Then it might be time for a CLA. It could be a case of a "bird in the hand"... where fixing your known camera is better than anything you could buy. Or you could just look for cameras where the seller says it recently had a CLA.