This week an essay called "We Are the Last People Who Know How It Works" climbed to the top of Hacker News. The subject is big infrastructure: the retiring engineers who still understand the decades-old code running banks, tax systems, and power grids, and the fact that when they go, the working knowledge goes with them.

It is a real problem, and it is not confined to nuclear plants and the Treasury Department. Your business has the same problem. It is just smaller, quieter, and in one way worse. At your scale there is usually no backup at all.

The one-person system

Think about the software your business actually depends on to take money and serve customers. The booking system. The inventory spreadsheet that grew into something nobody would still call a spreadsheet. The website a freelancer built four years ago. The little app that syncs orders between two tools you use every day.

Now ask a harder question. For each of those, how many people understand how it actually works, well enough to fix it when it breaks?

For most small businesses the honest answer is one. Sometimes zero, because the one person already left.

Engineers have a blunt name for this: the bus factor. It is the number of people who would have to get hit by a bus before a system stalls because nobody left knows how to keep it running. One analysis of popular open-source projects found that most had a bus factor of two or fewer. Those are projects with public code and multiple volunteers looking at it. The custom system running your business was probably built by one person and has never been read by a second.

Why it stays hidden

Working software does not ask for attention. It just runs. The freelancer who built your site moved on, and for a year nothing went wrong, so it never came up. The employee who owns the inventory process is good at it, so you never had a reason to have anyone shadow them. The code has no documentation because it worked fine without any.

The danger is not the day the person leaves. It is a random Tuesday six months later, when a payment provider changes something, or a plugin update breaks a page, or the sync quietly stops, and the only person who understood the moving parts is unreachable. Now you are paying someone to reverse-engineer your own business under pressure, which is the most expensive way to buy anything.

If it is any comfort, the largest organization on earth has not solved this either. The Government Accountability Office reported in 2025 that ten federal agencies were running critical systems decades old, eight of them on outdated languages, some on COBOL, with a "dwindling number of people" who can support them. The federal government spends more than $100 billion a year on IT, and roughly 80 percent of that just operates and maintains what already exists. Six years after flagging the ten most urgent systems, agencies had modernized three.

Read that again. Effectively unlimited budget, and the constraint was not money. It was that the systems had outlived the people who understood them, and you cannot hire understanding of a system that was never written down. A small business has no way to brute-force that problem the way Washington can try to. Which means the only real strategy is to avoid creating it in the first place.

Four things worth more than they cost

Count your bus factor. Literally list the systems your business could not operate without for a week, and next to each one write the name of the only person who truly understands it. The list is usually shorter and scarier than owners expect. That list is your risk, ranked.

Treat documentation and access as deliverables, not favors. When you pay someone to build or run software for you, the working code, a plain description of how the pieces fit together, and the credentials all belong to you. If handing those over feels like a big ask, that reluctance is the tell. Our guide on hiring a developer without getting burned goes deeper, but the short version is that a professional expects to hand you the keys, because locking you in was never the point.

Own the accounts. The domain, the hosting, the code repository, the admin logins. All of it registered in the business's name, not a contractor's personal email. This is the single most common way small businesses get frozen. Not sabotage, just a freelancer who drifted away holding the only copy of the front-door key.

Prefer boring and documented over clever. A system a second person can pick up and understand is worth more than a brilliant one only its author can. That is not a knock on talent. It is the whole definition of maintainable software, and it is the difference between an asset you own and a dependency you rent from one person's memory.

The quieter story

The value of a system was never just that it works today. It is that someone other than the person who built it can keep it working tomorrow. That is why, when we build custom software or take over a maintenance contract for a business in Northwest Arkansas or anywhere else, the documentation and the account handover are part of the job, not an upsell. Real upkeep is part of it too, which is more than most maintenance plans actually deliver.

The essay at the top of Hacker News is about the people who know how the old machines work. The quieter version is every business, large and small, that never noticed how few of those people it had. Count yours before something breaks and counts them for you.