When spreadsheets break — five signs

Almost every company we talk to runs something important in a spreadsheet. And almost every one of them apologises for it. There's no need: a spreadsheet is an excellent tool. It's there instantly, everyone can use it, it adapts in minutes — no rollout project, no permission concept, no training.

Which is exactly why it stays long after it stopped fitting. The switch doesn't get postponed because nobody sees the problem, but because nobody can say when the point is reached. It isn't "too many rows" — sheets with 40,000 rows run fine.

It's five other signs. If two of them apply, you're there.

1. There is one person who "does" the file

Not: who maintains it. Who knows why column AF is hidden, which of the three total rows is the real one, and why row 214 must not be sorted.

That person isn't a risk because they work badly, but because their knowledge is written down nowhere. While they're on holiday, everyone else is working in a file they don't understand — and rightly doesn't dare to change.

The test for this is uncomfortably simple: let somebody else make a change that touches a formula. If a phone call happens, you don't have a file, you have a dependency.

2. There is more than one truth

stock_2026.xlsx, stock_2026_final.xlsx, stock_2026_final_NEW_JH.xlsx. Or more subtly: one file on the server and a copy on a laptop, because there was no connection in the van.

From here on, every number is a guess. Not because anyone is careless, but because the format has no answer to the question of which version counts. Two people working at the same time necessarily produce two states.

Cloud spreadsheets soften this without solving it: they answer "which file", not "which value". Two people editing the same row still overwrite each other — just faster.

3. Everyone sees everything

The file with the hourly rates sits in the same folder as the one with supplier terms, and the staff list has salary three columns further right. Whoever has access to the folder has access.

This goes unnoticed for a long time and then all at once — during a dismissal, with an intern, at the first subject access request. A spreadsheet cannot do field-level permissions, and folder access is the crudest possible instrument for the job.

4. Nobody can say who changed what

A price is wrong. An appointment has vanished. A quantity reads zero. In a spreadsheet, "who did that?" is unanswerable — at best there's yesterday's backup, and even that only tells you that something changed.

As long as it's internal numbers, that's annoying. As soon as record-keeping duties are attached — working hours, inspection records, batches — it's a defect, not an annoyance.

5. The work happens outside, the sheet lives inside

The clearest sign. The fitter writes on paper, the driver sends a voice message, the carer notes it on the back of a hand — and in the evening somebody transfers all of it into the sheet.

That transfer is pure double work, and it's where the errors come from. A spreadsheet is not usable on a phone: not with gloves, not standing up, not one-handed. When your work happens where your software can't reach, a pile of notes grows in between.

What a spreadsheet genuinely cannot do

The five signs share one cause. These aren't features that are missing — they are properties a file cannot have in principle.

That's why "let's rebuild the sheet properly" never helps. A better spreadsheet is still a file: one state, one level of access, no trace, no rules. You cannot improve a file until it becomes a system.

What it costs to leave it

The reflex is: "it works though." It does — the cost simply sits somewhere nobody adds up.

Sign	Where it surfaces	What it actually costs
One person "does" the file	Holiday, illness, resignation	A standstill exactly when nobody has time to catch up
Multiple states	Numbers that don't match	Every report needs a reconciliation round first
Everyone sees everything	Staff changes, access requests	An incident that can no longer be contained
No trace on changes	Complaints, audits, disputes	One account against another instead of a record
Capture only in the evening	Every day	Double work plus the errors from transcribing

None of these appear on an invoice. Added up, they are regularly larger than the software that would have replaced them.

The switch doesn't have to be big

The usual reflex is to turn five signs into one large project: replace everything, all at once, a year of rollout. That's the reason it mostly never happens.

The reverse works better — replace the one sheet that hurts most and leave the rest alone. One area, solved cleanly, is worth more than ten that half-work. That's what the kit is for: you take the module that solves your problem and snap more on later.

How to pick the right sheet: not the biggest one, but the one other people wait for most often. The biggest file is usually well maintained — otherwise it would never have grown that far. The damage happens in the file three departments need at the same time.

And the data from the old sheet comes along. How that works in practice — mapping columns, duplicates, free-text fields grown over years — is in the piece on moving out of your old system. What you need for it isn't a decision about the next ten years, but an afternoon with a CSV file.