Preventive maintenance Preventive maintenance is a time-based maintenance. Timing may be based upon the use of hours and pre-determined interval. This kind of maintenance anticipates failures and adopts necessary actions to check failures before they occur. It heavily depends on the prior knowledge that certain parts do need replacement in specific time interval. It is carried out with specific objectives like detecting and locating weak areas and ensuring perfect functioning, by even replacing certain critical parts which could still be used. Planned preventive maintenance is regular, repetitive work done to keep equipment in good working order and to optimize its efficiency and accuracy. This activity involves regular, routine cleaning, lubricating, testing, calibrating and adjusting, checking for wear and tear and eventually replacing components to avoid breakdown.