The spreadsheet that almost ate tax season

The file was named ClientList_2026_FINAL_final2.xlsx. That name is the whole story. Diane runs the tax prep office I keep running, and in February her second preparer, Marlene, worked a full Wednesday off a week-old copy of their client workbook. She re-quoted forty-one clients at last year's prices. Nobody caught it until the appointment letters went out.

Their filing system is a USB stick that lives in a drawer by the coffee maker. Whoever has the stick has the current file. Whoever doesn't has a copy they emailed themselves Tuesday night. That's the system. That's the system that failed.

Three people editing one file that is the whole business need that file in one place. Microsoft 365 Business Standard is the boring, correct answer, and it costs $12.50 per person per month on the annual commitment. I pay for Diane's three seats on my card and she squares up with me quarterly, same as the hosting.

What it costs

Business Standard is $12.50 a seat a month on the annual plan, $150 a seat for the year. Month to month it's $15. Business Basic runs about $5.92 a seat, call it $71 a year, but that tier only gets you the browser and phone versions of Office plus the business email. Real Excel, the one that runs Diane's fee macros, starts at Standard. Premium is $22 and bundles security stuff a five-person office doesn't need yet.

Here's the part I find quietly funny. Microsoft now sells Standard without Teams for $9.29. That plan only exists because enough customers complained about paying for a chat app they never open. I still buy with Teams. The difference is about $38 a seat a year, and Diane's son logs in from college every March to help with data entry, and Teams is how he asks where the bathroom schedule went.

There's a free version too. Word and Excel in a browser, 5GB of OneDrive. It's real and it's fine for a household. It is not fine when the file is the business.

How I set it up for the office

1. Bought three Business Standard seats on the annual commitment. That's $37.50 a month, $450 a year, on my card.
2. Assigned a license each to Diane and Marlene, one to the shared bookkeeping mailbox. Every seat counts, even the mailbox.
3. Installed the desktop apps from the admin portal. The browser versions are not the same program. Diane's fee calculator runs on old macros, and macros are a desktop thing.
4. Made one shared document library in OneDrive and moved the client workbook in. Then I confiscated the USB stick. It's in my toolbox now, holding screws.
5. Turned on version history so nobody has to remember to save copies. OneDrive keeps the old ones by itself.

Setup took one afternoon, maybe four hours, most of it moving files and re-pointing Diane's letter templates at the new folder. Unwinding Marlene's forty-one re-quotes took longer than the whole install.

The tool crib version

A shared library is the tool crib at the supply house. One pegboard, one of each wrench, painted shadows where each tool hangs. You check it out, you bring it back, and there's never a question about which one is real.

The USB stick system is every guy keeping his own wrenches in his own truck. Nobody knows which torque wrench is calibrated. Somebody charges for a condenser off a bent ruler, and the customer gets the bill. Diane got that bill in February, in letter form, forty-one times.

The complaints about Microsoft are real, and they're mostly about the box, not the tools. People gripe that the price creeps while Microsoft bolts on stuff nobody asked for. There's a Copilot upsell living in the corner of every window now, $30 a seat on the business side. Ignore it. The web versions are thinner than the desktop ones, and the storage math is confusing, 1TB per seat in OneDrive plus a separate shared pile in SharePoint. I moved the one workbook in and left everything else where it was.

What people praise, and I agree: the desktop Excel is still the best spreadsheet ever made, and two people can sit in the same file at once without destroying it. Diane and Marlene watched each other type in real time and both made the same face. Like the coffee maker had learned to talk.

What to do Monday

Open the business file you'll touch most this week. If the name has FINAL or (2) in it, you've got Diane's old system with a different drawer. Make a folder in OneDrive tonight and move that one file in. Not the whole business. One file.