All original and renewal plumbing licenses shall be good for one year or two years from the date of issuance as determined by the plumbing board, except that any license may be revoked or suspended by the plumbing board at any time upon a hearing upon sufficient written, sworn charges filed with the plumbing board showing the holder of the license to be incompetent or guilty of a willful breach of the rules, regulations, or requirements of the plumbing board or of the laws or ordinances relating thereto or of other causes sufficient for the revocation or suspension of his or her license, of which charges and hearing the holder of such license shall have written notice.