What are the relevant warranties?

Roofing materials will come with product warranties. But you should also inquire about whether the contractor guarantees the labor and installation itself. Reputable roofers will stand behind their work with a labor warranty.

What are your payment terms?

Ask what forms of payment the contractor accepts. More importantly, inquire about any deposits that are necessary. Any deposit shouldn’t be more than about 10% of the total estimate, or be paid until the materials arrive at the work site.