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

https://brooksfznx367.theburnward.com/managed-decline-can-you-plan-replacement-without-an-emergency

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