It really depends on a few factors. One is how well the firearm is maintained. And what chambering and how hot a load is being shot out of it. The 220 swift was a good one for burning out barrels rather quickly. But you get something like a 45-70, 35 rem. these will last forever if they are cared for.
Regardless, with the average shooter/hunter, you can expect a firearm to last his or her lifetime. Now a competetive shooter that shoots thousands of rounds a week or month. They will require more replacement of parts through normal wear.
I have rifles for over 40 years that still shoot very well.