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

https://www.active-bookmarks.win/single-ply-roof-guarantees-usually-cover-15-20-years-reflecting-the

Single ply roof guarantees usually cover 15-20 years, but the actual roof can last 25-40 years with proper care. Guarantees mainly protect against manufacturing faults, not wear and tear or poor maintenance