Years ago I read a running book that suggested one should alternate feet for breathing - so, breathe in 3 and out 2, (or in 4 and out 3, in 2 and out 3) would mean your next breath would begin on the opposite foot. - it had to do with evening out any additional burden for the legs, I think.
Have any of you heard of this? It took me a while to get in the groove of 3 and 2, but I've adapted to doing it.
One thing this helps is counting stride per minute as it is a multiple of five, I just count my breaths.
I'm new to this forum and look forward to reading your experiences.