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

https://delta-wiki.win/index.php/How_Do_Seams_Fail_on_Single_Ply_Roofs_Over_Time%3F

Single ply roof guarantees usually cover 15-20 years, but the real service life can stretch 25-40 years if maintained right. Guarantees focus on material defects, not wear and tear or weather