Obsolescence is the loss of value or usefulness of an item due to changes in technology, fashion, customer preferences, or other factors. Obsolescence is considered a carrying cost, because it is an expense associated with holding inventory over a period of time1. Carrying costs are the various costs a business pays for holding inventory in stock, such as warehousing, insurance, taxes, depreciation, and opportunity costs2. Obsolescence can increase the carrying costs of inventory,because it can reduce the demand and sales potential of the item, and may require the item to be written off or sold at a lower price3.

The other options are not considered carrying costs, because they are not related to holding inventory in stock. Setup is the cost of preparing a machine or a process for production. Transportation is the cost of moving goods from one place to another. Scrap rate is the percentage of defective or unusable units produced in a process. These costs are more related to production or distribution activities than inventory holding activities.