I use a bit of split testing at QS and I know I've written about it before. The concept is simple: in my case, I send out a newsletter with slightly different titles to 20% of the list and see which one wins. That winner gets sent out to the entire list. One hurdle I face is the guessing game of "why did they choose this one? What can I learn for the future?" Sometimes I think that I don't need to split-test something because it's simple and that's bad thinking.
You always split-test.
You do it because one title will always outperform the other and that competition helps your message get out.
Typically, one headline beats another by about 11% with our newsletter. That's a several-hundred-person difference.
Even if all I'm doing is living in the moment, cranking out two headlines with a slight difference and not getting into the psychology of WHY people prefer one... I still get more eyeballs.
Even if I don't learn a thing for the next newsletter, I still get 11% more opens. That's more people reading our content, learning about the site, engaging with our writers and community, laughing and internalizing that QS is where you go if you want to make more profitable trades in Magic.