Single ply roof guarantees often cover 15-20 years, but the roof can last 25-40...

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

Single ply roof guarantees often cover 15-20 years, but the roof can last 25-40 years with the right care. Guarantees typically focus on materials, not wear and tear or maintenance