The hidden cost of losing know-how

Picture a building where the boiler trips a few times each winter. Only one person, say Ray, can get it going again without a service call. He knows which fault to look for first, the restart steps in the manufacturer's manual, and which trips mean stop and call for service, not reset. When Ray is on vacation, the building goes cold and someone pays for an emergency call.

Now picture a customer site that only one tech, say Lisa, has ever worked. She knows the gate code, which key opens the roof hatch and that the north units need the long ladder. When Lisa is out sick, the job gets moved or someone spends an hour on the phone.

Or picture a press that needs a trick after every die change, say a feed setting to check before the first hit. One setup person knows it. Everyone else finds out the hard way, with a bin of scrap.

Know-how nobody wrote down

These gaps stay hidden because everything works while the person is there. Nobody notices that the job depends on one person's memory until that person is out sick, on vacation or gone for good.

The people who know the most have usually been there the longest. In the Bureau of Labor Statistics' January 2026 figures on employee tenure (opens in a new tab), workers ages 55 to 64 had been with their current employer for a median of 9.6 years, more than three times the 3.0 years for workers ages 25 to 34. The longest memories belong to the people closest to retirement.

Four kinds of know-how at risk

These four kinds are the easiest to lose, because they almost never get written down.

Context

Why things are the way they are. Why the shop stopped buying from that supplier. Why the north roof units get serviced first every spring. Without the context, the next person undoes a decision that was made for a good reason, then learns the reason again the expensive way.

Failures

What broke, why it broke and what fixed it. Crews fix the problem, get the line running and move on, and the write-up never happens. A year later the same failure shows up, and nobody remembers the cause.

Who to call

The person at the parts counter who still knows the old part numbers. The inspector who wants to see the test tags first. The facilities manager who answers texts but never email. These relationships take years to build, and they usually live in one person's phone.

Judgment

When a pump starts sounding like that, shut it down and call someone. When the readings look fine but the unit smells hot, keep looking. Judgment is pattern recognition built over years. It's the hardest kind of know-how to pass on and the most valuable, because it keeps small problems small.

What it really costs

The cost rarely shows up on one line of a budget. It's spread across everything else:

• Downtime. The machine sits while someone works out what the old hand would have known in five minutes.
• Callbacks. A tech goes back to a customer because the first visit missed what the regular tech always checks.
• Rework. Parts get scrapped, or a setup gets redone because a step was missing.
• Safety. People improvise when they don't know the right way, and improvising around power, pressure or heavy equipment gets people hurt. Don't fill the gap with a guess. Stop, follow the procedure and lockout/tagout, and ask.
• Slow ramp-up. New people learn slowly when the only way to learn is to find the right person and hope they have time.

To size it in your own shop, count the service calls one of your own people could have handled, the callbacks to sites only one tech knows and the scrap after setups.

Why manuals and wikis don't get updated

Your shop probably has a binder, a shared drive or a wiki with a few good pages and a lot of empty ones. They don't stay current, for three reasons.

Writing is slow. Writing up a fix properly can take longer than the fix. Busy experts put it off, then forget the details.

They live somewhere else. The binder is in the office. The know-how is needed at the machine, on the roof or in a customer's basement.

They capture the what, not the why. A procedure lists the steps. It rarely says why step four comes before step five, and that's exactly the part that walks out the door.

Capture it when it comes up

Instead of asking experts to write everything up, catch know-how when it comes up anyway: at the end of a job that taught you something, right after a breakdown while the cause is fresh, or when someone asks a question and gets a good answer.

A minute or two of talk at those moments, recorded on a phone, beats an afternoon of writing a month later. It happens where the work is, and it includes the why, because people explain the why when they talk.

Before someone leaves

Retirements are usually known months ahead. Start a structured handover then, not in the last week, when it's too late for follow-up questions:

1. List what only that person knows: the equipment, the sites and the contacts.
2. Break the list into items small enough to record one at a time, like "what to check when the boiler trips."
3. Have them record each item at the machine or on the site, a minute or two each.
4. Have the person taking over listen and ask follow-up questions while there's still time.
5. Check items off as you go, so you both see what's done and what's left.

What to measure

Skip vague goals. Three simple measures tell you whether this is working:

• Questions answered from saved notes. How often do people find the answer in a note instead of tracking down a person?
• Equipment and places with notes. How many of your machines, units and sites have at least one useful note?
• Things only one person knows. How many machines and sites have notes from only one person, or none at all? That number should go down over time.

A 90-day plan

Month 1

1. List who might leave in the next two years, through retirement or otherwise.
2. For each of them, list what only they know, and mark what would hurt most if they left tomorrow.

Month 2

1. Pick one person from your list and their top five items.
2. Run the handover steps above for those five items.

Month 3

1. Check whether the next person used the notes on a real job.
2. Fix what was unclear, and record again where needed.
3. Spread to the next person on your list, then to the next crew.

Do it with people, not to them

This only works if experienced people want to take part:

• Credit people. Name the person whose note saved the day, and make sharing something people are recognized for.
• Let them choose. People decide what to share and how to say it.
• Don't use their notes against them. A note that admits a mistake, or shows the real way differs from the written procedure, is a gift. Thank them, and take it to whoever owns the procedure so it gets fixed. Never use it to assign blame.
• Don't use it to push people out early. Saving what someone knows protects the shop when they leave on their own terms. It's not a way to replace them sooner.

Do it that way, and people will share more than you ask for. Do it the other way, and the best know-how stays where it is until the day it leaves.