Preventive maintenance (PM) is managed service that attempts to prevent breakdown or serious problems with an item. In preventive maintenance, calls are created according to a predetermined, regular schedule.

During the PM call, a service technician performs services on an item already in the installed base. These services typically involve cleaning, diagnostic checking, and replacement of consumable items such as inks, lubricants, toner cartridges, and high failure parts. Preventive maintenance is essential in some industries, such as aircraft maintenance, and has become standard in others, such as business copiers.

Without preventive maintenance, the traditional service contract is more or less an insurance policy, an agreement protecting the customer when something goes wrong with a product. With preventive maintenance, the service contract becomes a tool for managing an ongoing service relationship involving regular service engineer visits. Service contracts offer full preventive maintenance scheduling.