Single ply roof guarantees usually last 15-20 years, but the real service life...

https://padlet.com/sirachapeteengtx/bookmarks-j04qs0veeiy5e2o1/wish/O7A9QmyNP25lQ6x3

Single ply roof guarantees usually last 15-20 years, but the real service life can often stretch to 25-40 years. The guarantee covers specific issues, not everyday wear and tear or poor maintenance