Planned Preventative Maintenance ('PPM') or more usual just simple Planned Maintenance (PM) or Scheduled Maintenance is any variety of scheduled maintenance to an object or item of equipment. Specifically, Planned Maintenance is a scheduled service visit carried out by a competent and suitable agent, to ensure that an item of equipment is operating correctly and to therefore avoid any unscheduled breakdown and downtime. Planned maintenance has some advantages over Condition Based Maintenance such as: Disadvantages are: