More important, legitimate, established and reputable contractors tend to find enough work through word-of-mouth referrals that they don't need to go door to door to attract customers. Be especially skeptical if the contractor drives a vehicle with no company name, no phone number or with out-of-state license plates. "Do not let these people enter your home," Johnson warns. "Often they want to be invited inside to see if something is worth stealing." 

Also, be sure to ask for proof that he or she is insured, licensed and bonded. "Homeowners that check out contractors beforehand and research their credibility are usually more satisfied with the job than if they abruptly chose a contractor," says Jeremy Zidek, communications coordinator for the Better Business Bureau in Alaska.

"I have materials left over from another job."
Sometimes contractors will offer a discount for the job under the pretense that they have extra materials and want to use up their supply. The truth is good contractors order enough supplies to meet the needs of each job, as often the price for supplies is typically included in the contract. Further, if a contractor has materials left over from a previous job and is making them available to you, he either didn't finish the job or is cheating the previous customer. Or, he may have never had a previous job but has materials to make it look like he did.  

"I want cash up front."
This contractor will take your money and disappear before or (even worse) after your project gets under way. It can be frustrating trying to chase after him, getting him to come back and finish the job, or hiring someone else to clean up a messy work site.  Don't ever pay in full for a project before any work has been done. Note: You may be expected to pay a down payment. "The contractor may not want to block out time in his busy schedule without some money up front," Levinson says. He recommends creating a payment schedule with the contractor at the start -- wherein you pay some portion only upon completion of a project. Johnson swears by the one-third theory. "The most I will ever give somebody up front -- after I have called references and checked him out -- is one-third of the money," he says. He gives them another third when the project is halfway done. "Their profit is in their last payment because that's what going to keep them on the job."