A reputable roofing contractor will always be insured
They should have things like worker’s compensation and liability insurance–to avoid putting you or their workers at risk. They should also be happy to show you these documents upon request.
A reputable roofing contractor will always give you everything in writing
Whether this is an agreed upon date of completion or the cost of goods and labor–everything your contractor promises should be in written/contract form. Those dates and costs should always be met unless there is written notice or a recorded agreement of change
A reputable roofing contractor has plenty of references and a high BBB rating
If a roofing contractor has reached the level of expertise and is trustworthy, they should have a ton of people for you to call to recommend them. Also, very few to no BBB complaints. Good reviews online in general too.
A reputable roofing contractor should be extremely clear and communicative from the very first moment
If you have to wait on calls back or an estimate of costs before you sign a contract, you will definitely have the same issues once the job is landed. For this reason, go with a roofing contractor that shows you how important your time and job is to them from the get-go.