Jack Daniels' generally advocates a "2-2" breathing pattern, meaning you breathe in every two steps, breathe out every two steps. However, Daniels' emphasizes that on an "easy run" you should be able to breathe 3-3 or 4-4 without any problem.
I personally think 2-2 is the most economical and only use 3-3 as a way to force myself to go easy. What about you all?