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

https://www.red-bookmarks.win/single-ply-roof-guarantees-usually-cover-15-20-years-while-the-actual-service

Single ply roof guarantees typically cover 15-20 years, but the actual roof can last 25-40 years with proper care. Guarantees focus on workmanship and materials at installation, not everyday wear and tear