It is surprising how anyone can call themselves a "contractor" and go into business.   Other professions and businesses which have so much potential for harm to consumers (medicine, law, accounting, architecture, engineering, surveying, banking and lending, investment brokers, insurance brokers, even barbering) are licensed, highly regulated and policed.  Yet homeowners routinely place their most valuable asset and their financial security into the hands of a contractor and are then totally at the contractor's mercy.  Thankfully, most contractors are ethical.  However, when they aren't, the losses in money and emotions they cause are huge!

You do have to have a license to be a contractor.

There is no major obstacles in becoming a licensed contractor, all you really need to do is pony up some money for the license fee and possibly show proof of insurance.