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

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

Single ply roof guarantees usually cover 15-20 years, but the actual service life can stretch to 25-40 years if looked after properly. That’s because guarantees focus on material faults, not wear and tear or maintenance issues