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

https://hectoruwog494.image-perth.org/why-do-some-single-ply-roofs-fail-in-the-first-10-years

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