Colt preban circa '93 in 7.62 x 39.

Guesstimate approx. 5,000 to 10,000 rounds of Russian through it. No real problems except the occasional misfeed probably mag related.

How does one know when parts should be replaced??  It shoots better than my eyes can see, barrel spotless, looks like some wear on the pivot pin, and the cotter pin (that's probably not the right name for it)  looks a bit worn.

I had a gunsmith check it out before firing and he didn't recommend any new parts. Just wondering if I should do some preventive maint.

ps I like the round and am wondering what should be my second AR brand in this calibre

Thx!

Keep shooting it.  

Upon each cleaning, always inspect the parts for any damage, or undue wear, especially on the bolt/lugs.  Would not hurt to have the headspace checked for the seriously anal.  Other than that, keep shooting it.