The unit economics spreadsheet nobody opened
It lived on page four of a Notion doc, was updated quarterly, and was wrong by sixty percent. Nobody noticed until the term sheet.
Say a founder's deck lists CAC at $1,200 and LTV at $8,400. Both numbers have sat on that slide for eighteen months. Both are wrong. At that company, fully loaded, CAC is closer to $2,100; after realistic churn, LTV is closer to $5,300. The founder has been quoting a 7-to-1 ratio. The one he has is 2.5.
He learned it the way founders usually do. An investor recomputed the numbers live during diligence, on a shared screen, in about fourteen minutes. The recomputation was quick. The rest of the round went to recovering from it.
Unit economics is the one metric whose drift stays invisible until it turns catastrophic. ARR sits on a dashboard. Burn sits on a dashboard. Pipeline sits on a dashboard. CAC and LTV rarely do, because they take a small monthly act of accounting discipline that nobody owns by default. Left alone, the numbers drift the wrong way with the reliability of a fridge left open. Silent the whole time. By the time the room is warm, the food has already turned.
The two errors are predictable. CAC gets reported lean: sales salaries excluded, marketing tools excluded, the contractor running paid acquisition somehow off the books. It gets the friendliest denominator, the customers who closed because of marketing rather than every customer who closed. LTV gets reported generous: contribution margin gross rather than net of customer-success cost, churn averaged over a flattering cohort. Both push the ratio the same way. Both happen without anyone deciding to lie.
The correction is small enough to be embarrassing. One number. One named owner, usually the head of finance, sometimes the founder. One thirty-minute monthly review, pulling inputs from the same systems every time. A monthly cadence catches drift inside one quarter. A quarterly cadence catches it inside four, which is too late if you happen to raise in month two.
Founders who can recite their current CAC and LTV from memory raise faster than founders who look them up. Not because investors quiz them. Because the recitation reveals who has been running the company on the real numbers and who has been running it on the deck. The first kind raises. The second kind explains.
The unit economics slide is a claim. The spreadsheet behind it is the evidence. If you haven't opened the spreadsheet this month, the claim is probably false in the direction that costs you most. The next term sheet is the audit you never ran on yourself. Run it first.