Method and user device for monitoring a use condition

A user device comprising:

• one or more sensors;
• and
• a controller, the controller including
• a baseline level of performance determination module adapted for determining a baseline level of performance for each of one or more elements of the device including a determined replacement threshold level;
• a diagnostic module adapted for triggering a running of a diagnostic in addition to an expected periodic diagnostic, which determines the current performance of at least some of the one or more elements for which a baseline level of performance has been determined, wherein the running of the diagnostic in addition to the expected periodic diagnostic includes a diagnostic determination triggered by a detected non-standard use condition by a non-standard use condition detection module;
• a comparator module adapted for comparing the current performance of the at least some of the one or more elements to the determined baseline level performance for the respective ones of the one or more elements of the user device;
• and
• a user notification module adapted for notifying the user of a need for service of the user device, when the determined current performance of at least one of the one or more elements falls below the determined replacement threshold level.