California Code, Business and Professions Code - BPC § 7335

(a) The license of an apprentice shall expire two years from the date the license was issued, or on the date the apprentice is issued a license following the license examination, or if the apprentice fails the license examination twice, on the date the results of the second examination are issued, whichever occurs first.

(b) No person holding a license as an apprentice shall work more than three months after completing the required training without applying for and taking the examination for licensure.

(c) The board may extend the two-year or three-month period described in subdivisions (a) and (b) upon a showing of good cause which shall include, but not be limited to, delays in applying for and taking the examination caused by the illness of, or accident to, the apprentice, or service in the armed forces of the United States.