The short answer
A customer can create value after the first order, but future revenue does not pay today’s advertising bill until it is collected. For acquisition planning, use a stated time horizon and contribution after servicing those future orders, not an unlimited lifetime-revenue promise.
Define the cohort and horizon
Group customers by acquisition period and calculate what happened over a consistent elapsed time. Separate realized contribution from projected contribution. A recently acquired cohort has not had the same opportunity to repeat as an older one. Mixing their raw totals can make retention and payback difficult to interpret.
Payback occurs when cumulative contribution per customer covers CAC
Follow a bounded example
Illustrative inputs: acquisition cost is $50 per new customer. First-order contribution after fulfillment but before acquisition is $30. During the next observation period, 25% of the original customers make one repeat order contributing $24. That adds 0.25 × $24 = $6 per original customer on average. Cumulative contribution is $30 + $6 = $36, leaving $50 − $36 = $14 of CAC unrecovered.
The 25% repeat share is an assumed example, not a benchmark. Additional future orders cannot be counted as realized payback until observed. A forecast should identify the data used to estimate those orders and explain how costs and cancellations are treated.
Keep customer value separate from revenue ROAS
Adding projected lifetime revenue to first-period campaign revenue can make a return look larger without changing current cash flow. If you report a lifetime-value-to-acquisition-cost ratio, label it separately and use matching horizons and cost definitions. Do not combine a gross-revenue lifetime value with a contribution-based interpretation.
Check financing and sensitivity
A model can show eventual positive contribution while cash is tied up in inventory or customer payment terms. Review when expenses are paid and collections arrive. Test lower repeat purchase and lower contribution scenarios before relying on delayed payback to justify a higher acquisition budget.
If there is not enough history, use the first-order model as a clearly bounded starting point. “Unknown” future value is more informative than a precise lifetime estimate with no defensible input data.
Build an age-based payback table
- Gather: Track acquisition cost and cumulative realized contribution per original customer at each horizon.
- Produce: Mark the first observed point where contribution covers acquisition cost, if it does.
Decision boundary: Do not fill unobserved periods with forecast values and label them actual payback.
Next reading
Examples are illustrative, not client results or benchmarks. The calculations use the inputs shown; real-world decisions depend on your records and assumptions. Report a correction.