(1) The sheriff shall keep the board informed by periodic reports of the employment needs of the office.
(2) The board shall as often as necessary conduct tests to establish lists of persons eligible for the various positions.
(3) Such tests shall be public, competitive and open to all persons who may be appointed under the criteria set by the commission. Such criteria may set limitations on residency, age, health, habits, moral character, and other necessary prerequisites for the performance of the duties of the positions.