How do I know the contractor or person I am working with is reputable?

Check with the state contractors licensing board and contact the local Better Business Bureau.  Also contact local building inspectors for recommendations.  They know who does quality work in your area.  Also contact the local county courthouse and ask the clerk to do a search of the local records of the person or company name to find out if there are local lawsuits filed or pending against the company.    You might find that a company has been sued for not completing jobs and having filed bankruptcies, for which you would have no future recourse.