General, specialty, and licensed contractors
Contractor licensing is one of the most fragmented areas of professional regulation in the United States. Some states license general contractors at the state level through a dedicated board, others license only specialty trades such as electrical, plumbing, and HVAC work, and a number of states leave general contracting to counties and cities. Whether a license is required usually depends on the type of work, whether the project is residential or commercial, and the dollar value of the job, since many states set a project-value threshold below which a license is not needed.
Homeowners, property managers, lenders, and general contractors hiring subcontractors all have reasons to confirm a license before work starts. An unlicensed contractor may be unable to pull permits, may not carry the bond or insurance the state requires, and in some states may have limited ability to enforce payment for the work. Checking the license also tells you which classifications the business holds, which matters because a license for one type of work does not automatically authorize another.
Contractor licenses are renewed on a fixed cycle set by each state, commonly every one to three years. Renewal usually requires confirming that the required bond and liability or workers' compensation coverage are still active, paying a renewal fee, and in some states completing continuing education on topics such as building codes, safety, or business law. Because the rules and amounts differ by state and by trade, rely on the official board for the current requirements rather than any general summary.
A good habit is to save a screenshot or printout of the license record on the day you sign the contract, and to check it again before the final payment. Licenses, bonds, and insurance can change during a long project, and a record from the board is far stronger evidence than a copy of a certificate supplied by the contractor.