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

https://www.bookmarks4all.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-service

Single ply roof guarantees usually cover 15-20 years, focusing on material defects and workmanship, but the actual roof can last 25-40 years with proper care