Single ply roof guarantees usually cover 15-20 years but the actual service...

https://telegra.ph/Incompatible-Adhesives-on-Single-Ply-Roofs---What-Happens-07-31

Single ply roof guarantees usually cover 15-20 years but the actual service life can stretch to 25-40 years with proper care. The warranty protects against manufacturing faults, not wear and tear or poor maintenance