Maintenance metrics are easy to generate and hard to choose. A system will happily produce thirty numbers a month, and a department that reports thirty numbers is reporting none of them. The measures worth keeping answer questions somebody would act on, and there are fewer of those than any published list suggests.
Schedule compliance, the one to start with
Of the work you planned for this period, how much actually happened on time. It is the most useful single maintenance kpi because it measures the thing you control, and because a plan nobody completes is not a plan. It also fails honestly: a compliance figure that sits near a hundred percent usually means the plan is too light rather than that the team is superhuman, and that reading is itself worth having.
Planned versus unplanned, and what it is telling you
The proportion of work that was scheduled rather than a response to something breaking is the closest thing to a summary of whether the strategy is working. It moves slowly, which is a feature: it is hard to game in a month. Read it alongside schedule compliance, because a site can look well planned simply by planning very little, and the two numbers together make that visible in a way either alone does not.
Wrench time, and why it is uncomfortable
Wrench time is the share of a technician's paid hours spent actually working on equipment rather than travelling, waiting, finding parts or looking for information. Measured honestly it is usually far lower than anyone expects, and it is the measure that points at planning rather than at people: most of the lost time is waiting for something the planner could have arranged. That is exactly why it belongs on a planner's list and why it is the least popular number to publish.
Choosing from the maintenance kpis examples you will find
Published lists run to twenty or more maintenance performance indicators, and most sites should keep four or five. The test for each is simple: if this number moved, what would we do differently. Maintenance performance metrics that fail that test are reporting, not management. Write the intended response next to each measure before adopting it, and the list shortens itself.
Questions people ask about maintenance metrics
What is the single most useful maintenance KPI?
Schedule compliance, how much of the planned work actually happened on time. It measures what you control, and a suspiciously high figure usually means the plan is too light, which is useful too.
What is wrench time?
The share of paid technician hours spent actually working on equipment rather than travelling, waiting or finding parts. It is usually much lower than expected and points at planning rather than at people.
How many maintenance metrics should a department track?
Four or five. The test for each is what you would do differently if it moved; anything failing that test is reporting rather than management.