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

https://www.romeo-bookmarks.win/single-ply-roofs-often-come-with-15-20-year-guarantees-but-they-can-last-25-40

Single ply roof guarantees usually cover 15-20 years, but the actual roof can last 25-40 years with the right care. Guarantees focus on materials and installation, not wear and tear or neglect