Don't be victimized by someone making a door-to-door presentation, offering to do repair jobs or home improvement on-the-spot, and requiring a cash deposit. An enterprising contractor may take the door-to-door sales approach. However, even on the smallest job, you must get proof that the person you are dealing with has a contractor's license in the trade for which you expect to have the work done. Get a written contract that contains all the details of the job to be performed.