Be sure to give them a list of other clients if possible. to help them get referrals. If the roofer is having trouble with his or her job, it is a good idea to have them refer you to another contractor. A good contractor is a great investment. It is important to get one that is reliable, affordable and knows how to complete a roof. It is a good idea to check out what types of insurance they have, because this is very important in this industry and in life. Your roof can be one of the most important investments you will ever make.