Single ply roof guarantees, usually 15-20 years, cover materials and...

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

Single ply roof guarantees, usually 15-20 years, cover materials and workmanship but don’t always match the actual roof life, which can be 25-40 years with proper care. To get the most from your roof, arrange regular inspections and clear drains annually