What's actually going on
This is a normal tipping point, and it rarely means the tool failed.
When a service business says Sheets stopped being enough, it's almost never one vague thing. It's usually one of a short list of specific breaks.
- Two people edit at once, and one change lands on top of another. Or one is mid-edit while the other reads a number that's about to move.
- One person built the formulas and nobody else will touch them, so the sheet only changes when that person is free.
- Nobody checks the version history, so a wrong number never gets traced.
- The sheet was built for how the business worked a while back. Every new client, service or staff member has arrived as a new tab or a new colour, rather than a proper column.
None of these means the spreadsheet failed. Each one is separate, nameable, and it's rarely all four at once.
Naming the one you actually have is what tells you the fix.
The smallest fix you can do today
Start with who can edit the file.
Google Sheets supports permission-based sharing. You can give people view-only or comment-only access and keep edit rights to a short list (Google). Check who has edit rights today and cut it to the smallest group that genuinely needs them. That alone stops most of the overwriting.
If the trouble is a tangle of tabs that get copy-pasted into each other by hand, IMPORTRANGE can help. Google's function pulls a range from one sheet straight into another (Google). It avoids retyping values every time something changes. You must grant permission the first time you use it. It can slow down on very large ranges, so check the size before relying on it.
When it's worth keeping, cleaning, connecting, or converting
Keep the spreadsheet if what's wrong is a habit. Nobody locked down edit access. Nobody was ever named as the sheet's owner. Fixing a habit costs nothing, and the sheet keeps working fine.
Clean it if the sheet has outgrown its own structure. Tabs may be bolted on over time, the same formula copied by hand across sheets, or a regular task may lack a consistent column. Restructuring one sheet properly is usually a matter of hours, not a new tool.
Connect it if the real gap sits between two things that don't talk to each other. That's the spreadsheet and an invoicing tool, or two people's separate "master" copies of what should be one sheet. Link them, or agree on one source, rather than keeping two versions of the truth alive.
Convert to dedicated software when several people need to edit different parts of the same record and need record-level permissions or an enforced workflow. Those limits may justify a change. The change log alone does not. Google Sheets keeps version history, though cell edit history may not show added or deleted rows, format changes or changes made by formulas.
What "done" looks like
Done is being able to say which of the four it was, and point at it no longer happening.
Not that you bought something and are hoping the feeling goes away.
The test is small and specific. The overwritten cell. The one person who has to be there. The "who changed this" moment. One of those stops, and stays stopped, for a few weeks running.
Two of you can be in the sheet on a Tuesday and neither of you loses a row.
If a different symptom turns up instead, that isn't failure. It's the next real limit, finally holding still long enough to be named.