There is a significant difference between repair and maintenance. A repair is reactive, it is done when something fails, is broken or needs to be fixed, whereas maintenance is proactive, and a measure to limit, or even stop something breaking. Reactive maintenance or repair is far more costly than proactive maintenance, and ideally, you want to be doing ample amounts of the correct maintenance to not have to do repairs.
Reliability Centered Maintenance or RCM, is a process to determine the most efficient maintenance approach for a company, minimizing downtime and keeping physical assets running.
Originally a commercial aviation term, RCM was then adopted by the United States Military, later by the commercial nuclear power industry and finally by other commercial fields and industries years later.