What term describes a good or service where all units are interchangeable?

The term that describes a good or service where all units are interchangeable is a standardized good. Standardized goods are homogeneous products that are identical and thus can be exchanged easily without any differentiation. This interchangeability means that consumers do not perceive any difference in quality between the units of the good, and they can substitute one unit for another without impacting their satisfaction.

For example, commodities like wheat or crude oil are standardized because one unit of these goods is essentially the same as another unit, allowing them to be traded in large volumes on markets without concerns over the differences in individual units.

In contrast, unique goods, specialty goods, and customized products involve differentiation where each unit has its unique features or qualities. This can lead to variations in consumer preferences and pricing, making them less interchangeable than standardized goods.