We just retiled our place as part of a complete reno of a fixer upper.
The previous terracotta tiles were still functional, but approaching end of life (estimated at 5-10 years left by a family friend who is a retired roofer with 50 years experience).
They were installed in 1934!
Wow ! Yes - we'd heard the stories - tiles getting water logged, breaking all the time, chipping in the cold (we get below zero in winter) etc - but never seen the evidence in our houses.
We were told they get to a point where you can change them - but they won't really get any worse.
80 years sound good to me though !