In short
Cost per lead is only half of a fraction. The other half is what a customer is worth, and without it a cheap lead and an expensive one cannot be compared at all.
Two engagements in our library make the point better than any framework: a school lead at $61 and a construction lead at $12.
The two leads
The construction company generated 422 leads at $12. The private school generated 306 leads at $61. On cost per lead alone the first account is five times better, and that comparison is meaningless.12
| Construction | School | |
|---|---|---|
| Cost per lead | $12 | $61 |
| Illustrative close rate | 1 in 10 | 1 in 10 |
| Cost per customer | $120 | $610 |
| What a customer is worth | One project | Several years of fees |
The number almost nobody has
When we ask a prospective client what a customer is worth over their lifetime, most cannot answer, and a good proportion have never separated a first purchase from a repeat one. That is not a criticism. It is the single highest-return piece of unglamorous work available to most businesses, and it costs nothing but an afternoon with the sales records.
- 01Average first purchase valueFrom invoices, not from memory.
- 02How often they come back, and for how longTwo years of history is enough to estimate from.
- 03Your gross margin on thatRevenue is not the number to optimise against.
- 04Your actual close rate from enquiryCount enquiries, not qualified leads, or you will flatter yourself.
Sources
- Construction Company: 422 leads at $12. Monastic Marketing case study. Read September 29, 2026.
- Educational Institution: 306 leads at $61. Monastic Marketing case study. Read September 29, 2026.