Preventive maintenance is maintenance carried out at predetermined intervals, or corresponding to prescribed criteria, and intended to reduce the probability of failure or the performance degradation of an item.
Central to preventive maintenance is the proactive approach that involves looking ahead and anticipating problems and preparation for the future in the present.
Maintenance tasks are planned, programmed and budgeted in advance. Maintenance tasks are normally conducted at regular, scheduled intervals based on statistical data, anticipated useful life, manufacturer’s recommendation and targeted performance standards.
A form of preventive maintenance is cyclical maintenance. This is a special situation where the same maintenance tasks are performed on a prescribed interval (cycle). Measure of ‘prescribed interval’ is normally based on time, e.g. every 3 months.
Another form of preventive maintenance is service maintenance. This is maintenance performed to meet equipment manufacturer's recommendations.
Examples of maintenance tasks are inspection, diagnosis, performance testing, monitoring, measurement, adjustment, lubrication, and small parts replacement.
Costs of maintenance are primarily the costs of labour, consumables and small parts and such costs are expensed in the reporting period when the costs are incurred.