Originally Posted by jmfisch409
I find that after 100 yards or so, that I'm not getting enough air breathing every third, so now I switch back and forth from left to right, breathing every second stroke, occasionally going every third.
I'd suggest that you not wait until 100 yards before you start breathing more frequently. You should try to balance left side and right side breathing, but breathing every 3rd stroke isn't the only way to do this. You can breathe for awhile on only one side (every 2nd stroke), then take 3 strokes and start breathing on the other side (every 2nd stroke).
If you run up an oxygen deficit before you switch to more frequent breathing, it's likely to make you feel out of breath and disrupt your stroke the rest of the way.