AR Bolt and CG wear and replacement.

[RTH1800]

I was reading a thread that got wild and in the mess somewhere wear and replacement of bolt and BCG on AR 15/M16's was mentioned.
What is the norm on that? I have fired some of my bolts on several barrel wear out cycles and never needed to replace parts.
Thanks.
RTH

 

[XLR308]

That's a good one, so 8620 steel wears out before aluminum upper ?
First I've ever heard of such but will be keeping up in case I learn something new.

 

[Gasgun]

I doubt that one would ever wear out a bolt carrier.
However, bolts can eventually fail. They usually break locking lugs or crack at the cam pin hole.
Having a couple of spare bolts around is cheap insurance.