A Glock doesn't need a recoil buffer. I guess maybe change the recoil spring periodically (every 5k-10k rounds). And, certain springs may wear out over time. But many people have gotten over 100,000 rounds thru a Glock easily. And, the first thing that typically "wears" out is the barrel over the 100K mark. I've read some stories of people having 150,000-200,000k thru their Glocks.
I seriously doubt U will get that many rounds unless U fire the gun several times a week. And, if U DID shoot out the barrel, just replace the barrel.
I have a Glock 34. And, while I have other guns that I prefer - I will admit that a Glock will typically have the longest lifespan of probably any other semi-auto pistol.
Don't worry about the lifespan. Really, any semi-auto will outlast U. The only decent fullsize gun that could possibly have an issue is the Beretta 92. And, all that gun requires is that the locking block be replaced. So, pick a gun U like. Don't worry about the supposed lifespan. It is doubtful U will wear out the gun unless you are a F/T competitive shooter.