A very important question you should ask your roofing contractor is: how long is my warranty on workmanship and materials?
Don’t assume that there is an industry standard, because there isn’t. Warrantees vary from the “tail-light warranty” where; once you’ve seen the contractors tail-lights, you’ll never see them again, all the way to the industry leading warranty that Affordable Quality Roofing offers: 25 years on workmanship, and 20 years to limited lifetime warrantees on materials (depending on your roofing material of choice).
This is by no means standard! The average warranty in Vancouver is 5-10 years on Materials and 5 years on labour. The second aspect: workmanship warranty, is the most important, because no matter how good the material, if it’s installed incorrectly, the material warranty is no good, literally: most manufacturers require that your roof be properly installed in order for the manufacturers warranty to be valid!