Single ply roof guarantees often last 15-20 years, but the real service life...

https://www.bookmarking-jet.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-roofing

Single ply roof guarantees often last 15-20 years, but the real service life can stretch to 25-40 years with proper care. Guarantees cover materials and installation but don’t account for wear and tear or weather