What is a CMMS?

A CMMS — computerised maintenance management system — is software that keeps a record of the equipment an organisation maintains, and of everything that has been done to it. The name is forty years old and sounds heavier than the idea. Strip it back and a CMMS answers three questions: what do we look after, what happened to it, and what needs doing next.

Before software, that record was a filing cabinet, a wall planner and an engineer who had been there eleven years. The cabinet is fine until someone needs it from a roof in the rain. The engineer is fine until they retire.

What a CMMS actually holds

Implementations vary enormously, but almost all of them are built around the same few records:

• An asset register — every machine you are responsible for, with its make, model, serial number and where it is. This is the spine; everything else hangs off it.
• Work orders — the instruction to go and do something, and the record of what was done when someone did.
• Maintenance history — dated visits against each asset, so the question "has this happened before?" has an answer.
• Parts — what is fitted to each machine, what was changed, and when.
• Documents — manuals, wiring diagrams, service bulletins, attached to the machine rather than filed by supplier.

Bigger systems add planned maintenance schedules, spare-parts stock levels, meter readings, labour costing and compliance reporting. Those are real features with real value, and they are also where most of the cost and most of the abandoned implementations live.

Reactive, planned, and why the distinction matters

Maintenance work divides roughly into two kinds. Reactive — something broke, go and fix it. Planned, or preventive — it is due a service, go before it breaks.

A lot of CMMS marketing is built on moving you from the first to the second, and for a plant with a hundred identical pumps on a duty cycle, that is exactly right. For a contractor maintaining other people's mixed equipment across forty sites, it is much less clear-cut: you often cannot schedule what you do not own, and the work arrives by phone regardless of what the plan said.

How it differs from the things it gets confused with

Field service management (FSM) overlaps heavily but points outward: scheduling engineers, routing them, quoting, invoicing, keeping the customer informed. Its centre of gravity is the job and the customer. A CMMS's centre of gravity is the asset — a difference worth more than a sentence, so there is a whole guide on the two.

Enterprise asset management (EAM) is a CMMS with the financial life of the asset added — depreciation, capital planning, disposal. Generally larger, slower and more expensive to put in.

A job or ticket system records that work happened. The difference is what survives: close a ticket and it goes to an archive nobody opens, whereas a CMMS files the same work against the machine, where the next person to stand in front of it will look.

The boundaries are soft and most products sit across them. What matters is which question the software is organised around, because that is what it will be good at.

Who actually needs one

The honest threshold is not a headcount. It is the first time one of these is true:

• More than one person works on the same equipment, so what one of them learned has to reach the others.
• You maintain machines you did not install and do not have the paperwork for.
• Someone asks what was done to a unit two years ago and the answer is a guess.
• A customer wants evidence of what you did, and a notebook is not evidence.
• The person who knows the site is about to retire, leave, or go on holiday during a breakdown.

A sole trader can hit three of those in a year. A ten-person firm has usually hit all five and is running on the memory of two people.

What makes them fail

Most failed CMMS projects fail the same way: the data entry burden lands on the person with the least time. If logging a visit takes eleven minutes on a laptop back at the office, it will not be logged, and within a quarter the system holds a fiction. Anything that is going to survive has to be faster to fill in than to skip, from a phone, in a plant room, with gloves on.

The second way is scope. Importing eight thousand assets before anyone has used the thing produces a large, accurate, unloved database. Putting the twenty machines you get called to most onto it, properly, produces something people open.

Where Repair Control sits

Repair Control is a CMMS built around the engineer on site rather than a planner at a desk. Every machine carries its own parts, manuals, dated visits and work orders, and the phone opens that record in front of the unit. Closing a job from the field is what writes the history, so the record is a by-product of doing the work rather than a second job afterwards.

It does not do preventive maintenance scheduling. Jobs carry a due date, but nothing recurs on its own, and there are no meter readings or stock levels. If a PM calendar is the first thing you need, we are not the right answer yet and would rather say so here than three weeks into a trial.

What it does have that most do not is an assistant that reads the specific machine's own record — its manuals, its part history, the tutorials your engineers filmed on it — and works from that rather than from generic knowledge. See how the asset record works, or what it costs.

Where next

• CMMS vs field service management software — why the two demo identically and solve different problems.
• What to put on an asset register — the fields that earn their place, and the identifier problem.
• How to write a work order — including what to do about the customer who will not sign.
• CMMS for HVAC contractors — if you maintain refrigeration and air conditioning you do not own.