Preventive Maintenance (or preventative maintenance) is maintenance that is regularly performed on a piece of equipment to lessen the likelihood of it failing. It is performed while the equipment is still working so that it does not break down unexpectedly.

The maintenance is scheduled based on a predefined time. A typical example of an asset with a time-based preventative maintenance program schedule is an air-conditioner which is serviced every year, before summer. A typical example of an asset with a usage-based preventative maintenance program schedule is a motor vehicle that might be scheduled for service every 10,000km.

In this Maintenance, the model schedule must be planned.  The Plan is based on when equipment failure might occur, and secondly, to prevent the occurrence of the failure by performing maintenance. Monitoring for future failure allows maintenance to be planned before the failure occurs.