The average elapsed time between the full restoration of an IT service or supporting component and the next occurrence of a failure to the same service or component.

A measure of product reliability that usually is given in units of hours. The higher the MTBF, the more reliable the product will be. For example, VIDAR digitizers feature a MTBF of 50,000 hours, the equivalent of nearly six years — the highest reliability in the industry.

MTBF ratings are measured in hours and indicate the sturdiness of hard disk drives and printers. Typical disk drives for personal computers have MTBF ratings of about 300,000 hours.This means that of all the drives tested, one failure occurred every 300,000 hours of testing. However, this is rather meaningless since most disk drives are tested only a few hours, so it would be unlikely for a failure to occur during this short testing period. A more useful gauge of a device's lifetime is how long a warranty the manufacturer offers.