There’s a ritual every founder goes through.

Open a blank spreadsheet.
Name it “Financial Model v1 FINAL.”
Spend three weekends building the thing that proves the business works.

Here’s what nobody tells you:
88% of spreadsheets contain material errors.
Not typos.
Formula errors that compound across the entire model.
That’s from a University of Hawaii study spanning 13 years of real-world spreadsheet research.

For a founder deciding whether to quit their job and go all in, a single wrong formula in the wrong cell can be the difference between “this works” and “I’m going to lose everything.”

I wrote an honest breakdown of when AI validation beats spreadsheets — and when it doesn’t. No hype. No “AI will replace everything.” Just a practical framework for which tool to use when.