Directors have to be elected every year, at the annual meeting of shareholders, even if your corporation consists of just one or two shareholders. See Cal. Corp. Code § 301. Directors then hold office until the next annual meeting of shareholders, barring a vacancy caused by resignation, removal, or death in office. (Vacancies can usually be filled by the directors themselves.) The articles of incorporation can provide for a shorter term of office to effectuate a “voting shift” (a change in the relative rights of classes or series of shares to elect directors as a class or series), but that is not something that will affect shareholders in a small corporation.