If you are an owner and contracting for work on your property the first thing you should do when interviewing prospective contractors is check the CSLB web site to determine if the contractor is licensed by the California State Contractors Board. Go to: https://www.cslb.ca.gov/OnlineServices/CheckLicenseII/CheckLicense.aspx
Make sure the license number given matches the name of the contractor. If it doesn’t there could be a problem with the person you are dealing with using someone else’s license number and not really being licensed.
Next check to make sure they have the correct license. A General Contractor normally hires subcontractors to perform the work but might have his own employees performing non-specialty work. For example he may have his own crew come own and perform demolition but hire an electrician to perform wiring on your project. If people are performing work on your project like electrical or plumbing make sure they have the proper license to perform that work. Likewise, prior to signing a contract with a General Contractor ask for the name and license number of the subcontractors performing the specialty work and make sure they are properly licensed to perform that work and have workers compensation insurance if they are not a sole owner doing all the work on the project.
There are numerous license classifications and you can view them on the CSLB web site: https://www.cslb.ca.gov/About_Us/Library/Licensing_Classifications/Default.aspx
If you discovery unlicensed contractors report them to the CSLB at: https://www.cslb.ca.gov/Consumers/Report_Unlicensed_Activity/
Protect yourself, you might be getting a great deal but if your house burns down because it was improperly wired or you end up with mold from improper plumbing you did not save anything.