Section 672.168 - Expiration date of certificates(1) Except as provided by subsection (2) of this section, all certificates expire one year after the date of their issue or renewal and become invalid on that date unless renewed. The State Board of Examiners for Engineering and Land Surveying may vary the dates of certificate renewal by giving to the applicant written notice of the renewal date being assigned and by making prorated adjustments in the renewal fee.(2) The board may vary periods of certificate renewal or periods for registration to provide for renewal and payment of fees either every year or every two years. If the board changes the renewal period it will provide written notice to certificate holders and registrants.