Closely related to expense classification by responsibility is the differentiation between controllable and noncontrollable expenses. Controllable expenses are those that are subject to the authority and responsibility of a specific manage. Care must be exercised because the classification of an expense item as controllable or noncontrollable must be made within a specific framework of responsibility and time. For example, the expenses of a particular responsibility center usually include some expenses, such as supervisory salaries, that are not ordinarily controllable within the responsibility center, but rather at higher levels of management. Within the responsibility center such an expense may be classified as noncontrollable. But when viewed in terms of larger organizational segments, or for the enterprise as a whole, salaries are controllable. Similarly, expenses such as depreciation usually are not controllable within the short run but are controllable in the long run. In the case of depreciation, management decisions about capital additions determine the subsequent depreciation expense amount. In the final analysis, all expenses are controllable, depending on responsibility and timing.