Expected life of a.22 LR?
Maybe 250,000 rounds, for a start. The wear of lead bullets on steel is essentially non-existent. You are more likely to damage the barrel from using cheap, multi-section cleaning rods and ill-fitting patch jags.
My High Standard match pistol has somewhere between 60-80k through it and it still will put 10 rounds into the X-ring of a 25 yard slow fire target from 25 yards, from a machine rest. Original springs, too.
With match ammo, of course.