Single ply roof guarantees, usually 15-20 years, cover product defects but...

https://www.bookmarkzoo.win/single-ply-roof-guarantees-usually-cover-15-20-years-but-the-actual-service

Single ply roof guarantees, usually 15-20 years, cover product defects but don’t always reflect the roof’s full service life, which can reach 25-40 years with good care. To help your roof last longer, get annual inspections by an SPRA-approved contractor