The focus on planning leads seamlessly to cost-based thinking. Costs lend themselves wonderfully to planning, because by and large they are under the control of the company. For the vast majority of costs, the company plays the role of customer. It decides how many employees to hire, how many square feet of real estate to lease, how many machines to procure, how much advertising to air, and so on. In some cases a company can, like any customer, decide to stop buying a particular good or service, and so even severance or shutdown costs can be under its control.