Well, fiddle strings eventually get brittle, but I don't know just how long it takes. I had this old guy, Marvin, in my music group whose parents bought him a Sears/Roebuck violin outfit when he was about 10. They also bought at the same time, a billion sets of strings. Marv never changed fiddles, and never changed a string until it broke. As he and the strings got older, that became more and more often. By the time he died, it was at least once per session.