MRO spending is usually a small fraction of a plant's total budget, but its impact on uptime is disproportionate — a five-dollar seal sitting in the wrong storeroom (or not in stock at all) can shut down a six-figure production line.
What counts as MRO
Typical MRO categories on a factory floor:
- Spare parts — bearings, belts, seals, gaskets, fuses, sensors
- Consumables — lubricants, cleaning agents, welding rod, filters
- Tools and equipment — hand tools, calibration gear, PPE
- Facility items — light fixtures, HVAC filters, general repair materials
The common thread: none of it ships inside the product. It exists to keep the equipment that makes the product running.
Why MRO tracking is its own discipline
MRO inventory has a different failure mode than production inventory. Running out of raw material stops a specific order. Running out of MRO stock stops the machine — and machines don't fail on a schedule. That unpredictability is why MRO tracking tends to live inside maintenance software rather than a general ERP inventory module: it needs to be tied to the asset it serves, the PM schedule that consumes it predictably, and the work order that consumes it unpredictably.
A CMMS that manages MRO well answers three questions fast: what's in stock, what's it for, and what happens to the next PM or work order if it runs out.