Re-roofing normally needs a permit
Replacing a roof covering is permitted work handled by the city where your house sits, or by the county in unincorporated areas. Minor repairs under the local threshold typically are not. Your contractor should say clearly which applies and pull it under their own licence.
You get an independent inspection
A permitted job is inspected by someone the contractor does not pay. For most homeowners that is the only outside check on workmanship the project will ever receive.
Unpermitted work becomes your problem
It reappears during resale, remodels, and claims — long after the contractor has moved on. Any discount offered for skipping it is borrowed from your future self.
Confirm the permit number
Ask for it, then confirm it with the city. That single check verifies both that the work is on the record and that the licence used matches your contract.
Frankly