Any order entered in accordance with the provisions of this chapter may be executed pursuant to its terms only by the investigative officers expressly authorized therein. The order may be executed according to its terms only during the hours specified therein, and for the period authorized or part thereof. No order may authorize the interception of any wire communication for any period longer than is necessary to achieve the objective of the authorization, nor in any event longer than fifteen days. Whenever an order authorizing an interception is entered in accordance with the provisions of this chapter, the order may require reports to be made to the panel showing what progress has been made toward achievement of the authorized objective and the need for continued interception. Such reports shall be made at such intervals as such panel may require.