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 manager. 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 noncontrolable. 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. The concept of controllability is useful for expense control if cost classifications are related to responsibility centers. Each expense in a responsibility center should be clearly identified as either controllable or noncontrollable within that particular center. To apply this concept, it may occasionally be advisable to establish two accounts for a particular type of expense in a responsibility center. For example, salaries can be separated in two accounts, Salaries---Controllable, and Salaries---Noncontrollable, and budgeted accordingly.