The primary goal of maintenance is to avoid or mitigate the consequences of the failure of equipment. This may be by preventing the failure before it actually occurs which Planned Maintenance and Condition Based Maintenance help to achieve. It is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. Preventive maintenance activities include partial or complete overhauls at specified periods. Workers can record equipment deterioration so they know to replace or repair worn parts before they cause a system failure. The ideal preventive maintenance program would prevent all equipment failure before it occurs.