One little known fact is that prior to July 1st, 2008, anyone could apply for a building permit without any qualifications. That changed after July 1st when Georgia implemented the State Contractor Licensing Program. The requirements are as follows:
Pass a backround investigation
Pass a financial solvency investigation
Pass a comprehensive compentency test in all facets of building construction
Pass a Georgia business law test as it applies to contracts, liability and insurance
As you can see, even if your project does not require a permit, a licensed contractor is "pre-screened" to a large degree by the state. In addition, poor performance by a contractor leaves the homeowner with a means of recourse by having the ability to report the contractor to the State. A licensed contractor is bound by the State to "make things right" or face having his/her license suspended or revoked.
Just because a contractor has a license to do business in a county DOES NOT mean that he/she is Georgia State Licensed Contractor. Ask them specifically if they are a Georgia State Licensed Residential Contractor.