<Tr> <Td> </Td> <Td> This article relies largely or entirely on a single source . Relevant discussion may be found on the talk page . Please help improve this article by introducing citations to additional sources . (May 2011) </Td> </Tr> <P> Planned preventive maintenance (PPM), more commonly referred to as simply 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 . </P> <P> Along with condition - based maintenance, planned maintenance comprises preventive maintenance, in which the maintenance event is preplanned, and all future maintenance is preprogrammed . Planned maintenance is created for every item separately according to manufacturers recommendation or legislation . Plans can be date - based, based on equipment running hours, or on the distance travelled by the vehicle . A good example of a planned maintenance program is car maintenance, where time and distance determine fluid change requirements . A good example of condition - based maintenance is the oil pressure warning light that provides notification that you should stop the vehicle because engine lubrication has stopped and failure will occur . </P> <P> Planned maintenance has some advantages over condition - based maintenance (CBM), such as: </P>

What are the various planned maintenance schedules that are generally used