Mouth to mouth recommendations have been going on since people have possessed language and to this day is still one of the best ways to find out how good a company really is. Not only do you get a rundown from someone you trust on said roofing company but you can also see first hand work and materials to know exactly what you are getting.
Research any company before you commit. A well skilled and experienced company with employees who possess excellent industry knowledge is more of a safe bet than a company who is new and is still learning its trade.
Online reviews are another excellent way of gauging a companies skill and repute. They are easily accessed and provide in depth analysis on specific companies. The only factor you need to be wary about is fake reviews that a lot of companies seem to be employing on bitter rivals.