The role left before the person did

She earned the promotion to operations lead. Six months later she is still running month end billing, because she is the only one who knows the seventeen unwritten steps between the timesheets and the invoices. The person hired to backfill her is doing the parts that had a checklist, which is about a third of the job, and nobody has left the firm.

The departure did not create the dependency. It exposed it.

Most roles in an established firm were never designed. They grew up around one person: the exceptions she learned to handle, the clients whose files she knew by heart, the order she ran the tools in because the order mattered and nobody else knew why. None of that lives in the job description. It lives in her.

When she moves on, whether to a new title or a new employer, the firm does not only lose labour. It loses operating memory. The replacement arrives with the same title and a third of the job, because a third is what was written down. The rest surfaces one missed step at a time, usually in front of a client.

Hiring faster does not close that gap. Even when the date is known months ahead, the capture rarely happens. APQC's 2025 survey of 1,000 professionals found that 92 percent of organizations do not consistently capture knowledge from people they already know are about to retire. If a scheduled retirement does not trigger it, a two week notice never will.

Nobody has to leave for the role to walk out

Parental leave does it. A three week vacation does it. A bad flu in the wrong week does it. Every one of these is a normal event in a firm of twenty people, and every one becomes an emergency when the role only exists as a habit. They are one condition showing up in different clothes: the business is operated by people rather than by systems those people run.

A written role is the only one you can hand to anyone

Writing the role down does not mean a policy binder or a recording of someone talking through their week. It means a workflow: what comes in, what decision gets made, which tool it goes into, who owns it, what done looks like, and who updates the document when the step changes. That last part decides whether the document is still true in a year. A procedure without an owner drifts back into someone's head within a quarter.

This is also the difference between a firm that can adopt new tools and one that cannot. Software, and now AI assistants, take a task that has a shape and run it. If the shape exists only in one person's head, there is nothing to hand the tool, and the firm ends up paying for the same undocumented step twice: once when it slows every departure, and again when it blocks every attempt to automate it.

Written roles are not a project you finish. They are a rule: every new recurring task gets added to an existing workflow or gets a new one, on the day it starts. Firms that hold that rule stop having departure crises, because a departure becomes a handover.

Start with the task nobody else can do

Pick one person the firm could not afford to lose next month. Ask them to list what they do that nobody else can, and why. Then take one item from the list, the most frequent one, and write it down as a workflow this week: inputs, decision, tool, owner, what done looks like, who keeps it current.

One task is enough to start, because the point is not the document. The point is the habit of never letting a new task settle into a person instead of a system. The next departure will tell you whether it took.