A single ply roof guarantee usually covers 15-20 years, but the actual roof can...

https://caidenaope074.trexgame.net/single-ply-vs-epdm-which-one-lasts-longer-on-a-warehouse

A single ply roof guarantee usually covers 15-20 years, but the actual roof can last 25-40 years with the right care. Guarantees mainly cover materials and workmanship, not wear and tear or damage