I was never good at maths at school, thankfully email marketing doesn't require you to be math wizard.
But it DOES help to know this simple equation when regularly sending emails to your list.
After you see the break down of these numbers, you'll think twice about believing that occasionally sending an email to your list (with high open rates).
It's like shooting your profits in the foot.
Oh and if you're curious what I'm doing to build my list right now - here's the resource I mentioned.
https://julesdan.com/gptgift/