A short CAC payback period looks attractive, but it can mislead if customers churn soon after acquisition or if early revenue carries weak gross margin.

Use gross profit, not revenue

Acquisition cost is recovered from contribution, not headline billings. Direct inference and support costs belong in the calculation.

Add retention to the view

Two channels can have the same six-month payback while producing very different lifetime economics if one cohort churns after month seven.

Track by cohort and channel

Enterprise sales, product-led growth and creator partnerships may have different acquisition costs and retention curves.

Include expansion carefully

Expansion can improve payback, but forecasts should use observed cohort behavior rather than assuming every account grows.

Bottom line

CAC payback is most useful when paired with gross margin and retention, not treated as a standalone growth score.