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

https://www.bookmarking-jet.win/single-ply-roof-guarantees-typically-cover-15-20-years-but-the-real-service

Single ply roof guarantees usually cover 15-20 years, but the actual roof can last 25-40 years with proper care. Guarantees often focus on materials, not wear and tear or maintenance issues