Measuring

One number decides everything in this course: what a customer costs through this channel, counted honestly. Take everything the channel consumed in the period — money spent, plus your own hours at the rate you defended in ENT-102 — and divide by the customers it produced. Not enquiries. Customers.

Including your own time is the step people skip, and it inverts the ranking more often than not. A channel with no cash cost that eats eight hours a week is frequently the most expensive thing in the business, and it looks free in every spreadsheet where the founder's hours are worth nothing. Once your hours carry the rate you would accept from an employer, the comparison becomes honest and sometimes uncomfortable.

Then hold it against what a customer is worth — contribution margin from ENT-103 if you have done it, or price minus direct costs if not — and against how many times they buy. A cost per customer above what they are worth is a business paying people to be its customers, which is survivable only briefly and deliberately.

Four weeks is the minimum honest window. Below that you are reading noise, particularly in a business with few transactions. And distinguish the two failures: a slow channel is producing something, improving, and simply has a longer cycle than you expected; a dead channel has produced nothing across a full window with reasonable effort and shows no movement in the intermediate numbers either. Slow deserves more time. Dead deserves the time back.