Once you have selected a contractor
Get proof of insurances. Do not leave yourself liable.
Get everything in writing! State law requires contractors provide written contracts to include payment schedule, time frame, detailed description of job and materials, and a third day cancellation clause and more.
Never pay the full price up front, but do expect to pay 1/3 to 1/2 job deposit, for which a contractor must be bonded or tell you where that money will be deposited in escrow.