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

https://www.pure-bookmark.win/single-ply-roof-guarantees-often-cover-15-20-years-but-in-reality-these-roofs

Single ply roof guarantees usually cover 15-20 years, but the actual service life often stretches to 25-40 years. That’s because guarantees focus on materials, not wear and tear or maintenance