The 14 Red Flags That Are Destroying Your Unit Economics
Key takeaways
Based on Chapter 1 of The Two Numbers
- Using revenue instead of gross margin inflates LTV by 30%+.
- Blended channel reporting hides which channels actually pay back.
- Most CAC numbers exclude salaries, content, and tools — and overstate efficiency.
- LTV calculated on too-short windows extrapolates from noise.
Quick Answer: Most companies make critical errors in how they calculate and manage LTV and CAC. Common red flags include using revenue instead of gross margin for LTV, counting only ad spend in CAC, ignoring payback period, and blending channel performance into meaningless averages. Lech Kaniuk identifies and explains how to fix all 14 red flags in "The Two Numbers That Build or Break Every Business."
Why Unit Economics Break
Unit economics don't fail because founders are bad at math. They fail because of invisible assumptions, incomplete data, and metrics that look healthy on the surface.
I've seen companies with dashboards full of green numbers heading straight toward bankruptcy. The numbers weren't wrong — they were just the wrong numbers. Years of operating and raising over €150M across my companies taught me to spot these patterns early, and many of them are lessons I've written up as essays.
Here are the 14 red flags I see most often.
Calculation Red Flags
1. Using revenue instead of gross margin for LTV
LTV must be calculated on profit, not revenue. A €100 customer with 30% margin is worth €30, not €100.
2. Only counting ad spend in CAC
Fully loaded CAC includes salaries, tools, agencies, content production, and overhead. Your real CAC is often 2-3x higher than your "marketing CAC."
3. Ignoring payback period
A 4:1 ratio with 24-month payback is more dangerous than a 3:1 ratio with 6-month payback. Cash timing kills companies.
4. Blending all channels together
Your blended CAC might be €150, but paid social is €80 while events are €500. Averages hide where you're actually losing money.
5. Using company-wide averages instead of segments
Enterprise customers might be 5:1 while SMB is 1.5:1. Blended metrics lead to blended (wrong) decisions.
Strategic Red Flags
6. Assuming current retention will continue forever
Many LTV calculations assume today's churn continues forever. It won't. New competitors, product fatigue, and market changes erode retention.
7. Counting expansion revenue you haven't earned
Predicted expansion is not realized expansion. Don't count upsells until they actually happen.
8. Ignoring negative LTV segments
Some customer segments destroy value. If you're not tracking separately, losers hide behind winners.
9. Optimizing for lead volume instead of lead quality
10,000 leads that convert at 1% with low LTV are worse than 1,000 leads that convert at 10% with high LTV.
10. Not including customer success costs
High-touch customers with low LTV can destroy margins. If support costs aren't in gross margin, you're overestimating profitability.
Cultural Red Flags
11. Celebrating "growth" that's actually cash burn
Growing 50% YoY means nothing if each customer costs more than they return. Growth without unit economics is just dying faster.
12. Using vanity metrics to justify bad economics
"Brand awareness is up 40%" means nothing if LTV:CAC is below 1:1. Brand value should show up in the numbers.
13. No one owns the LTV metric
When LTV is "everyone's job," it's no one's job. Someone needs to be accountable for improving customer value.
14. Recalculating only once per year
If your LTV and CAC are 12 months old, you're making decisions based on fiction. Markets and businesses change constantly.
Related
Go Deeper
This post identifies the problems. "The Two Numbers That Build or Break Every Business" by Lech Kaniuk shows you how to fix them:
- The complete calculation methodology for accurate LTV and CAC
- The Stratification Model: how to segment your analysis correctly
- How to build LTV and CAC accountability into your org
- The Value Driver Framework for evaluating every initiative
- Case studies of companies that fixed these mistakes
This article draws on Chapter 1 of The Two Numbers, which covers why founders get unit economics wrong, and the fixes that move the numbers in full detail.
Next step
Unit economics fundamentals
Read the foundational guide to LTV, CAC, gross margin, and how they fit together.
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Written by Lech Kaniuk, author of "The Two Numbers That Build or Break Every Business."