The specifics change between trades, but the questions that protect you do not.
1. Are you licensed and insured, and may I have the numbers?
You want the DPOR license number and a certificate of insurance sent directly from the insurer, not a photocopy. General liability protects your property; workers' compensation protects you if someone is injured on your job.
2. Who is actually doing the work?
Ask whether the crew is employed by the company or subcontracted. Neither answer is disqualifying, but it changes who is accountable and whose insurance applies.
3. What is the payment schedule?
A deposit is normal. A demand for most of the money before materials arrive is not. Tie payments to milestones you can see.
4. What is not included?
The most expensive surprises come from scope gaps: permit fees, disposal, patching drywall after the plumber leaves, repainting. Ask directly what the quote excludes.
5. What happens if you find something behind the wall?
Ask how change orders are handled and whether you approve them in writing before work continues.
6. What is the warranty on labor?
Separate from the manufacturer's warranty on parts or materials.
7. Can I contact two recent customers with similar jobs?
Not a reference list assembled for marketing, but two people with a job like yours in the last year.
General guidance only. For work requiring permits, confirm requirements with Prince William County or the Town of Haymarket directly.