California Code, Vehicle Code - VEH § 4609

The department may extend the life of the current series of license plates, outstanding during 1957, and may hereafter issue a new series of license plates for an indefinite period of time, but in no event for a period less than five (5) years.  During each intervening year of the period for which the plates are issued, the department shall issue a tab, sticker, or other suitable device as herein provided.

Any such series of plates may be canceled by the director with the approval of the Governor at any time after five years from the year of issuance of such series.