Single ply roof guarantees usually cover 15-20 years, focusing on material...

https://www.rankbookmarkings.win/single-ply-roof-guarantees-typically-cover-15-20-years-but-the-actual-service

Single ply roof guarantees usually cover 15-20 years, focusing on material defects rather than how long the roof will actually last. In reality, with proper care, these roofs can serve 25-40 years