Though not usual, I have a 1970s 22-250 Weatherby MK5 that was purchased in the States in the mid 80s. Since it was purchased, it ran at least 6000 rounds of hot loads before it gave up the ghost and was then re-barreled in 22-250 AI (waste of time over 22-250)
Using a bore scope will show the all important state of the barrel, but apart from any glaring marks or pitting, the throat is where the use will show. My OAL became longer throughout the life, but as long as you made the rounds to keep the distance from the Lans uniform, it kept the accuracy. I try to use an OAL guage when looking at used rifles, this will give you a good idea of how much throat is remaining.
Personally, I think I have been lucky, for the price difference between a new and second hand rifle would not make me buy anything other than a true bargain second hand.