Single ply roof guarantees often cover 15-20 years, but the actual service life...

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

Single ply roof guarantees often cover 15-20 years, but the actual service life can reach 25-40 years when properly looked after. Guarantees focus on defects, not wear and tear