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

https://www.click-bookmark.win/single-ply-roof-guarantees-often-cover-15-20-years-but-the-real-service-life

Single ply roof guarantees usually cover 15-20 years, but the actual roof can last 25-40 years with proper care. These guarantees often focus on material faults, not wear or external damage