A contractor license number is proof that your contractor is operating their business legally, that they have the proper documentation required by your state or region, and that they are competent in their area of work (electrical, plumbing, construction, etc.). Licensed contractors should freely advertise their contractor license number. If not, you can request it before considering them for hire. You can also research your contractor using their license number. The database for your state will indicate the field they are licensed to work in; whether they are up to date on insurance, workers’ compensation and bonds; and whether they have any consumer complaints issued against them. If the licensed contractor you are hiring does not have employees, they are not required to carry workers’ compensation. Each state or region will have their own database for licenses, such as the State of Oregon Construction Contractors Board. For more, check out our tips for smart hiring on Thumbtack.