So Cal Engineering

1. Get the license number and look it upAsk for the full business name and its license number, then look it up with your state. Not every trade needs a license in every state. License rules by state
2. Ask for proof of insuranceA current certificate of liability insurance, and workers' compensation if they have employees.
3. Get two or three written estimatesFor the same work, so you can compare them line by line. Get three pros
4. Put the job in writingWhat is included, the materials, the start and end dates, the total price and when each payment is due.
5. Do not pay it all up frontPay as the work gets done, and keep the last payment until it is finished. Some states limit how much a contractor may ask for up front.
6. Ask who will be at your homeThe owner, employees or subcontractors, and who to call if something goes wrong.
7. Get the warranty in writingWhat it covers, for how long, and what you need to do to keep it.
8. Keep your papers and photosThe contract, receipts, and photos before and after.

General information, not legal advice. Rules are different in each state.