At almost every company of 10 to 50 people, there's someone like this: knows where everything is, knows every client's exceptions, remembers why that one supplier gets paid differently. Usually one of the most valuable people at the company.
And also the biggest operational risk the company carries, without it showing up anywhere.
How to measure the risk
One question per critical process: if this person didn't show up for three weeks, what stops?
Make the list. Invoicing, collections, payments, payroll processing, the relationship with the accountant, bank access. If the same name shows up on more than two, the risk is concentrated.
There's a second, more uncomfortable test: can that person take two straight weeks of holiday without bringing their work phone? At many companies the honest answer is no, and that is the answer to the risk question.
Why this happens
Never out of bad intent. It happens because documenting takes time, because the person is efficient and solves things faster than they can explain them, and because while everything is running smoothly, nobody feels the problem.
Knowledge accumulates in exceptions: the client who needs the invoice split into two documents, the supplier who only accepts payment by the 10th, the figure that's calculated differently for one case. No single exception seems worth writing down. Together, they are the operation.
Documentation that's enough
You don't need a manual. For each critical process, one page with four points:
- What gets done, in order, with the dates it has to be done by.
- Where things are — systems, folders, credentials and who holds them.
- Known exceptions, client by client or supplier by supplier.
- Who to contact when something goes wrong.
One page per process, five or six processes. It's half a day's work per process, and it resolves most of the risk.
The test that confirms it
Documentation never tested is worth nothing. The test is simple: someone else runs the process from the document, with the author available but silent. Whatever forces a question is what's still missing from the page.
The side effect
There's a benefit rarely anticipated: the key person usually feels relieved. Being irreplaceable is often experienced as a cage — no real holidays, no changing roles, no growing into something else. Documenting frees them up for more valuable work.
It's also what makes it possible to decide clearly between hiring or outsourcing: without a documented process, either option just moves the dependency to a different name.