Single ply roof guarantees usually cover 15-20 years, but the real service life...

https://edwinzbme239.raidersfanteamshop.com/how-do-i-spot-a-quote-that-skipped-wind-uplift-checks

Single ply roof guarantees usually cover 15-20 years, but the real service life can be 25-40 years with proper care. That guarantee mainly protects against manufacturing defects, not wear and tear or installation issues