1) What is your specialty?
2) How many jobs like mine have you done in the last year?
3) Do you have any other jobs starting immediately before or after mine? (If so, make sure you specify start and finish dates in your contract, even requiring money penalties should your job not start/finish within a specific time frame. And ask more detailed questions if the contractor will be moving between job sites simultaneously, i.e Who is the point of contact person on my job? How much experience do they have? etc.)
4) What trade organizations do you belong to?
5) How long have you been in business? (Ask for business license & proof of insurance. If new, then what is their education/experience background? Someone new or working without a business license doesn’t mean you shouldn’t hire them, but their price should definitely be cheaper than someone with experience and in legitimate business for years.)
6) Who are your suppliers? Do you have an account with any suppliers? (If so, check to see if they are in good credit standing.)
7) What products/brands do you use?
8) Do you have any references from other jobs like mine? (Go see the reference/job in person if you can.)
9) Do you have a portfolio (or website, etc.) of your work I can see?
Tell me about a major problem/snafu you had with a job. How did you solve it?