[tlb]

He botches the math. 20% monthly churn means you have to replace your customer base 2.4 times over a year, not 8 times. But the conclusion is the same: CAC > LTV.

[shasta]

I assume his formula (1+monthly_churn)^12 – 1 was based on a misremembering or misunderstanding of annual churn = 1 - (1-monthly_churn)^12.

[andrew_null]

OP here. You're right, I'll update for math.