A firm incurs a cost when it uses a resource for some purpose. For example, a company
producing kitchen appliances uses certain resources, the costs of materials (such as sheet
metal and bolts for the enclosure), costs of manufacturing labor, and other costs. Often costs
are assigned into meaningful groups called cost pools. Costs can be grouped in many different
ways, including by type of cost (labor costs in one pool, material costs in another),
by source (department 1, department 2), or by responsibility (manager 1, manager 2). For
example, an assembly department or a product engineering department might be treated as a
cost pool.