It is difficult to predict a tyre's lifespan because it bears no relation to its manufacturing date. Tyres that have never been used, or have only been used infrequently, may still show signs of aging. Many factors can affect their lifespan: weather conditions, storing and usage conditions, load, speed, tyre pressure, maintenance, riding style...
Michelin recommends that all riders regularly dedicate a few moments of their time to inspecting their tyres in order to pick up on any external signs of aging or wear: deformations or cracks in the tread, on the shoulders or sides... You should also have your tyres checked by a professional who can assess if they should be replaced or not.
The 5 year test… before it's too late!
After 5 years of use or more, tyres should be examined every year by a professional mechanic. If the tyres need to be changed, follow the manufacturer's recommendations with regard to replacing original components. As a precaution, all tyres that have not been replaced after ten years should be changed, even if they appear to be in a generally good condition and have not reached their tread wear limit.