A system, method, and apparatus are provided for maintenance opportunity planning in a production line having a plurality of machines and buffers between machines on the production line, with the buffers processing production units between at least two of the machines. The system, method, and apparatus advantageously indicates maximum allowed downtime for a machine, through monitoring the status of the buffers to determine whether the flow of units through the buffers is favorable, monitoring the status of the plurality of machines, and determining which of the plurality of machines may be shut down for a particular period of time while substantially maintaining the favorable flow of units through the buffers. In this way, the inventive system and method saves time and resources by reducing production line downtime and unscheduled overtime.