I was a little questioning of why it was 3, but it isn&#x27;t an unreasonable ratio after some thought: 1 would be borderline absurd, 2 could work but might not work with your operational costs, and 3 should represent a reasonable return on investment.<p>There is probably a closer, more precise number, but 3 is a decent number to use; if you&#x27;re looking for businesses that generate a lot of revenue from customers, without spending a lot to acquire them or serve them; it works out.<p>Otherwise, great article and I will definitely be keeping this in mind in my own project. When I did the math it came out to 8.4, so I&#x27;ve got more wiggle room in the CAC than I thought.