Every licensee, in order to maintain his qualifications for any license held by him, must have been regularly engaged in the occupation for which the license was issued for no less than 21 working or racing days during the term of the license. Should a licensee not be so engaged for the period required, the Board may require that such licensee or applicant for renewal of a license re-establish his qualifications for such license.
Cal. Code Regs. Tit. 4, § 1509