Random or Rare-Event Failures

These failures occur in young stage of the machine. After passing over the infant stage, the machine will be running with its full efficiency and the user will enjoy its full fruit in this period only. The effective usage and correct maintenance can enhance this portion of its life. User's care may come down in this stage due to the facts that the user might have got boredom or monotony or some sort of negligence as he observes the machine will be working with full efficiency through much care is not taken. This act in fact may or may not result as failure immediately, but its impact will be there on long run by affecting its life and wear out of the parts, etc. However, the immediate failures are known as random or rare-event failures.

The reliability of machine will be very high in this stage. Usually preventive maintenance and breakdown maintenance are adapted in this stage to low cost failures while RCM (Reliability Centered Maintenance) and CBM (Condition Based Maintenance) techniques are employed on the machines that are high cost or in case the failure may lead to high cost or damage.