In granting a variance, the character and extent thereof shall be specified and the variance shall be made subject to such conditions and guarantees as are deemed necessary to secure conformance to the requirements set forth in Section 17.54.080. A variance may be made valid only for a specified term. If any portion of a variance is utilized, all of its conditions and specifications shall be operative, and the violation of any of them shall constitute a violation of this title. (Prior gen. code § 8-93.3)