A pay-per-use or metered-use computer uses a balance manager to monitor usage and update a value balance according to a first usage schedule when the computer is in active use. When the activity level of the computer is reduced below a threshold, the balance manager may update the value balance according to a second usage schedule. Activity level of the computer is determined by monitoring the activity level of a one or more components of the computer including input devices, communication controllers, and the processing unit. Rules can be applied to determine when to switch between usage schedules and if credits to the value balance should be made.