By Malcolm Schulstad & Aliesha Aden
What is your measure for maintenance success?
Is it about keeping costs down? Reduced unplanned downtime? Ensuring all of the planned maintenance work is ticked off and completed? Maybe you’re more advanced and focused on maximising production or even lifting OEE?
Don’t get me wrong, those things matter. If a plant is down, nothing else counts.
But here’s the problem… these metrics almost always sit secondary to other business priorities, like meeting production and sustainability goals. Once certain minimums are met, maintenance is often viewed as an unwanted cost. An area of expenditure that needs to be minimised.
Because the truth is, you can “win” on maintenance cost while quietly losing everywhere else.
That loss shows up in ways that often aren’t labelled as maintenance outcomes:
- Energy consumption creeps up and nobody notices (or nobody owns it).
- Parts get replaced early “just in case”.
- Consumables get burned because we don’t trust condition or data.
- Equipment gets run rough, hot, overloaded, misaligned, and we call it “normal”.
- Product quality drifts and scrap goes up, but it’s not labelled a maintenance problem.
- Assets get replaced earlier than they should, and we treat it like fate.
Rethinking how maintenance success is defined
So, I want to challenge the way we define maintenance performance.
What if maintenance success was measured by sustainability outcomes?
Outcomes that reflect how efficiently we use energy, materials, labour, and asset life.
Outcomes that create meaningful, long-term impact.
Traditionally, maintenance success is judged by questions like:
- Did we keep it running?
- Did we avoid surprises?
- Did we spend less this quarter than last quarter?
- Did we complete the maintenance plan?
These measures are fine from a short-term perspective.
But they don’t tell us how much waste we created, or prevented, across the lifecycle of the equipment.
The hidden waste maintenance doesn’t usually account for
In modern industry, waste isn’t just product in a bin. It’s also:
- Wasted energy
- Wasted labour time
- Wasted parts and consumables
- Wasted asset life
- Wasted product through instability, defects, and rework.
If we’re serious about sustainability, we need to stop pretending these aren’t maintenance outcomes too.
A better definition is this:
Maintenance and reliability exist to reduce total waste.
The core idea behind sustainable maintenance
Here’s the core idea:
Maintenance success = the lowest total resource intensity per unit of useful output, without increasing risk.
That’s it.
That definition respects production (that output matters), but it shifts the optimisation target away from “maintenance spend” and toward total waste.
And yes, that includes energy.
Because if an asset is degrading and drawing more power to do the same job, that’s not just an “energy problem”. That’s a maintenance problem too.
The new maintenance scoreboard
If I had to define a new way of measuring maintenance performance, it would look something like this.
Primary KPI: Total Waste Intensity (TWI)
TWI = Energy + Maintenance inputs + Quality losses, normalised by useful output.
In plain terms: how much resource did we burn, and how much waste did we create to produce what we produced?
This is the metric that forces an uncomfortable but important question:
Are we maintaining the asset, or are we just keeping it alive?
Supporting KPIs (so we can see what’s driving the number)
TWI is the headline score, but you still need to understand what’s driving it.
So the scoreboard breaks into three supporting outcomes:
1.Efficiency per running hour (or per unit output)
This goes beyond “how often did it break” and looks at:
- How much energy did it consume while it ran?
kWh per hour / kWh per unit
- How much maintenance time did we spend keeping it going?
Labour hours per 1,000 hrs / per unit
- How many parts and consumables did we burn through?
Parts + consumables per 1,000 hrs / per unit
- How much effort went into reactive work, diagnostic churn, and “we’ll just replace it” maintenance?
In other words, how efficiently did we convert operating time into useful work without feeding the machine unnecessary resources?
2.Asset life (and how quickly we consume it)
Most sites track failures. Some track MTBF. Few track how quickly asset life is being consumed.
Yes, asset life is one of the biggest sustainability levers available. Extending the working life of equipment avoids premature rebuilds and replacements and reduces waste at scale.
A lot of asset life is lost through very normal behaviours:
- Misalignment and imbalances
- Poor lubrication practices (too much, too little, wrong type)
- Overload and process instability
- Ignoring early-stage issues because “it’s still running”
- Treating vibration, temperature, or current drift as noise.
That’s why a supporting metric like degradation rate matters. Are assets trending towards failure faster, or are we flattening the curve?
If we can track and reduce the rate of degradation, we’re suddenly doing maintenance with a long-term view that has an actual impact on sustainability, not a short-term one that is simply reacting to current conditions.
3.Product waste (scrap, rework, yield loss)
This is where people often get defensive, because product quality often sits in another department.
But equipment condition drives process stability. And process stability drives quality.
If a pump is cavitating, a fan is fouled, a gearbox is degrading, or a motor is running inefficiently, the process can drift. When the process drifts, product gets wasted.
That’s not a “quality-only” issue. That’s a system issue.
The Guardrails
To be clear, this isn’t throwing away uptime, cost, or compliance.
They still matter. But they shouldn’t be the primary optimisation target.
They should act as guardrails that keep us honest while we optimise for what really matters.
So the focus becomes:
Optimise for resource efficiency and waste reduction (TWI + its drivers), while staying within guardrails for safety, compliance, reliability, throughput, and cost.
Because if someone claims, “We improved sustainability by doing less maintenance,” but unplanned downtime or cost doubles, then no, you didn’t improve anything. You just moved the pain.
An example: You could replace all your assets on a more frequent basis to run more efficiently, use less efficiently and require minimal maintenance, but you’re significantly increasing your costs and have excess waste through the assets that have been replaced.
What this shift changes in practice
This shift changes how maintenance teams are seen.
Instead of being the team that fixes what breaks and tries to spend less the following year, they become the team that actively reduces waste across the site.
That reframes the purpose of maintenance as:
- Keeping assets reliable and efficient
- Intervening when needed, not when the calendar says so
- Reducing energy waste caused by degrading equipment
- Extending asset life
- Preventing product loss caused by instability.
If we continue to measure maintenance success through cost and uptime alone, we will optimise for cost and uptime, even when that increases waste.
So if we genuinely want more sustainable industry, we need to change what “good” looks like.
Not with slogans.
But with what we choose to measure.
If you’re curious how your current maintenance strategy stacks up, try this:
- Pick one critical asset
- Look at how its energy use, maintenance effort, and output have changed over time
- Ask whether it’s becoming more efficient, or simply staying online.
You don’t need a new system to start this conversation. You just need to change what you’re looking for. Our team is happy to help you look at this with fresh eyes. Just drop us a line.