Abstract: A printer or photocopier operable at a plurality of different performance levels. A metering system measures usage of the device in units of use, and is configured such that the number of units metered for performing a particular task of the device is varied in reliance on a level of performance of the device for that task. In one form, the device includes a user interface for receiving user input indicative of a selected level of performance, the metering system being configured to utilize the selected level of performance in metering the usage. Alternatively, or in addition, the metering system is configured to determine the actual level of performance of the device and to utilize the actual level of performance in metering the usage. System components may be user replaceable modules.