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

https://melissafreshmaid.com/tpo-vs-pvc-lifespan-what-matters-more-than-the-material/

Single ply roof guarantees usually last 15-20 years, but the real service life can be 25-40 years when properly looked after. Guarantees cover materials and workmanship but don’t account for weather or wear