Around 5,000 rounds from me and I don't know how many from the first owner (first gun, bought it in a pawn shop in NM) and the dang thing is still as strong, shiny, and accurate as the day I bought it. And, about 500 of those rounds were +P+, as well as some of my own "home brew".
About the only problems that I've heard of in Revolvers is either cylinder lock due to using wrong type of ammo (too hot), the bore becoming smooth (rifling gets too thin), or it exploding.. again due to hot loads. I guess the springs can wear out or the firing pin breaks but never (knocks on wood right now) had it happen (any of the above except first one but that was my fault.. but the gun, a .38, fires the ammo (hot) with no problems now.. go figure).
USP45usp