Every founder can name their best channel. Almost none of us can prove it.

I have been having the same conversation with three different founders this month, and it always arrives at the same place.

Ask someone where their users come from and you get a confident answer in under two seconds. Ask how they know, and the answer gets softer. It usually turns out to be one of these:

• the dashboard says direct, so they went with the thing they remember doing that week
• a channel got credit because it was the last click, which mostly measures who reminded the person, not who convinced them
• they ran two things at once and gave the win to the one they enjoyed more

I have done all three.

Here is what made me stop trusting my own read. A channel can look enormous while it is being paid for, and the moment you stop paying, the number does not decay. It falls off a cliff. That tells you something honest and slightly brutal: it was never a channel, it was a receipt. You were buying visits, not building a way to be found.

The opposite also happens. A place that sends you five people a month for a year is easy to write off as noise, right up until you notice those five people behave completely differently from the hundreds. Low volume is not the same as low value, and a short measurement window makes them look identical.

What I have landed on, and I am not sure it is right:

Judge a channel by what it does when you stop feeding it. Anything that goes to zero the day you stop paying was rented. Anything that keeps trickling was earned. Both can be worth having, but only one of them compounds, and I think most of us are counting them in the same column.

The part I cannot resolve is timing. Earned channels take months to say anything, and a bad month looks identical to a dead channel. So you are choosing between quitting too early and pouring effort into something that was never going to work.

How do you personally decide a slow channel is dead rather than early? Not the theory, the actual moment you called it. I would like a rule I can apply on a Tuesday when I am tired, and I do not have one.