Single ply roof guarantees, usually 15-20 years, cover defects but don’t always...

https://shed-wiki.win/index.php/EPDM_Roof_Lifespan_-_Can_It_Really_Go_Past_35_Years%3F

Single ply roof guarantees, usually 15-20 years, cover defects but don’t always reflect the roof’s full lifespan, which can be 25-40 years with proper care. To help your roof reach its potential, arrange annual inspections and clear drains regularly