It depends.

Glocks and Rugers can usually run forever. Stainless steel pistols are more durable than carbon steel which is more durable than aluminum alloy. Charter Arms and Sigma tend to have limited lifespans before they loosen up. Vintage Airwieghts had problems with frames cracking within 500 rounds. Zinc framed pistols like Davis and Jennings in .380 tended to have slides crack within 100 rounds. Research the gun you want before you buy to learn about weaknesses and problems. Examine the frame and forcing cone for damage. Expect to replace the recoil spring and firing pin of a gun with a high round count, possibly the magazine as well.

People are not always honest about round count or use of +P reloads, or they may not know because they are not the original owner.