I have socks from 1989. *^).
There are folks shooting 1949 Grizzly bows, and early 50's Kodiaks. I have used 55/56 Kodiaks and they shot as well as new bows. You can have a $1000.00 custom blow up in a week, so nothing is ever perfect.
I have a '61 Polar and a '67 Shakespeare Necedah that I use on a regular basis....with low stretch strings on them. Go figure.
Usually, if a bow lasts a year or so, it will last a long time. Ol' Buck, a lemonwood selfbow, is traveling and still shooting...even after a repair 8^). He is over sixty years old.
Take care of them and they can be passed down to your grandkids.