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 stretch 25-40 years with good care. Guarantees mainly cover manufacturing defects, not wear and tear or maintenance lapses