It depends on how much you fire the gun. A gun is like any other mechanical device, parts wear out or sometimes break and whole gun eventually wears out. Some folks recommend recoil spring replacement on a regular basis. IMHO, if the spring is properly made, that should not be necessary in anything like normal use.
So what is normal use to me? I would say an average of 50 rounds a week would be high normal, 1000 rounds a week would be very high. A shooter who goes through 50k rounds a year would probably need a new gun every 2-3 years.