Abstract: Systems and methods for determining efficiency-of-use scores related to uses of a product by two or more users may implement operations including, but not limited to: associating a physical product with a first user in response to a signal indicating that the first user has control of the physical product; computing an efficiency-of-use score associated with a use of the physical product by the first user; associating the physical product with a second user in response to a signal indicating that the second user has control of the physical product; and computing an efficiency-of-use score associated with a use of the physical product by the second user.