Tires are supposed to age out after 5 years or so. My spare tire is over 10. Does it need to be replaced?
Yes, a good mechanic cycles the tires every service, and recommends switching all 5 before end of life. I’ve had better luck though convincing my clients to start changing tires one tire at a time starting 1.5 years before end of life at every service. Since a lot of clients don’t like shelling money for all 5 at the same time.
It’s been 9 years since I’ve been a mechanic, so take my advice for what you will.