Maintenance myth busting: How plants separate reliability facts from fiction on the factory floor

My podcast co-host Joe Kuhn has told me many times, when he walks into almost any plant and asks about reliability, he hears all the right answers. Kuhn has spent many years as a plant manager and now works as a consultant, and he’s heard it all.

We have a PM program. We have a system for tracking work. There are KPIs, dashboards, and reports that suggest everything is under control. But when he steps onto the shop floor, the story often changes. Many facilities believe they’re running effective maintenance and reliability programs, yet they’re not getting results. 

Joe and I often talk about the gap between what dashboards report and what technicians actually experience on the shop floor. This is where myths take hold, so the Ask a Plant Manager podcast is here with a reliability reality check. Listen to the podcast audio here.

What happens when we put reliability and maintenance assumptions to the test?

The following five scenarios break down some of the most common beliefs and misnomers in maintenance and reliability, separating myth from reality—and exposing where even well-intentioned programs can go off track.

1. More planned maintenance always improves reliability.

MYTH

It seems logical. If some PMs are good, more must be better. “That's a clear myth,” Kuhn says.

Increasing PM frequency without regard to actual equipment needs simply adds unnecessary work. “You’ve got to look at what the equipment needs, so more is not necessarily better,” Kuhn says.

In practice, this kind of thinking can lead to distorted KPIs rather than better outcomes. Teams inflate PM hours or reclassify work to appear more proactive. Meanwhile, the real opportunity to improve reliability through condition monitoring and on the right assets and problem solving gets ignored.

Kuhn emphasizes that PMs alone won’t improve reliability. “If you get really good at doing PMs, you're going to be horribly disappointed with the impact you're going to have on the bottom line, because you're not doing problem solving,” he says.

2. If PMs are completed, equipment will always be reliable.

MYTH

Even a well-executed PM program doesn’t guarantee reliability. “This has to be a myth,” Kuhn says. Completion metrics alone don’t reflect system health. Reliability is dynamic, not a fixed endpoint. “You never arrived at the perfect maintenance plan. You never arrived there,” Kuhn says. Maintenance programs are never completed or finished.

Reliability requires continuous evolution, replacing time-based maintenance with predictive approaches and solving root causes. It also requires collaboration beyond maintenance. “You must get production involved,” Kuhn says.

3. A CMMS will automatically improve maintenance performance.

REALITY

“I would say it's going to improve maintenance performance,” he explains, primarily because digitization reduces administrative waste and improves tracking, “but to what degree?” he questions. “It’s kind of a trick question,” he adds.

CMMS expectations often exceed reality, and they’re often sold as the “end all be all.” If you’re looking for a panacea, “You're going to be horribly disappointed with the overall impact,” Kuhn says.

More importantly, implementing a CMMS too early can be a strategic mistake. For highly reactive plants, Kuhn advises focusing first on fundamentals like lubrication, better motor management, and reducing emergency work.

“So any people want to start with something they could buy, instead of working on culture. Culture is always hard to work on, but culture is where all the results are,” Kuhn says.

4. High wrench time equals high productivity.

MYTH

Kuhn says wrench time is one of the most cited, and most misunderstood, maintenance KPIs. “I am very cautious of KPIs,” he adds.

His experience shows a consistent gap between reported and actual wrench time performance. “They'll tell me that the wrench time is, 40%, 45% and 50% and then, I organize an audit of that, and I've never, never, never, never, come out of a plant on day one with a higher wrench time than 15%. It’s never happened.”

The discrepancy comes down to flawed measurement and assumptions. Activities like preparation or delays are often counted as productive time, inflating results.

“A lot of times people don't know how to measure wrench time,” Kuhn says. Or work time gets billed as productive, when it includes unproductive work, such as searching out parts. If KPIs don’t reflect reality on the shop floor, they’re misleading.

5. Emergency work is unavoidable in manufacturing.

REALITY

While many reliability programs aim to eliminate emergency work, some level of reactive maintenance is both inevitable and acceptable. “Technically, this one is absolutely true,” Kuhn says.

Certain failures are best handled with a run-to-failure strategy, especially when the consequence is low and redundancy exists. For example, a pump that failed after decades of service: “The pump went out after 30 years’ worth of use, Okay, is that acceptable? Yeah.”

In such cases, aggressive root cause analysis may not be the best use of resources. “Do you need to root cause something that's happened once every 30 years? Probably not.”

That said, this doesn’t justify a reactive culture. “Don't take that as an excuse to have 90% emergency work. You must relentlessly pursue it,” Kuhn says.
The key is prioritizing frequent, high-impact failures rather than rare, low-risk events.

Don’t manage the myths; be the reality

Reliability isn’t driven by volume, tools, or metrics alone. It depends on judgment and sometimes a willingness to challenge assumptions.

Whether it’s questioning PM overload, auditing KPI accuracy, or resisting overengineered processes, your maintenance plan should be grounded in practical reality and what’s really happening on the plant floor.

The balance between rigor and pragmatism is what separates high-performing plants from those simply managing the numbers.