My understanding is that a little wear is ok as long as the balls, outer
ring, etc are not pitted or corroded. I think Joel had some thoughts on
swapping joints side for side or end for end on each axle. Check with him
about that. I do know that the wear alone is not reason for trashing or
rebuilding the joint--at least if it's not really bad. I've run 35K on joints
that showed wear but had good grease. Hope this helps.

Dan
87 Synchro GL