RichardSK, thanks, I often wonder that, did I spell breathe right or breath. Now I know.
I think it is important to be able to breathe to either side as well, and I think bi-lateral breathing is one of the best ways to add that to you arsenal. Terry put it really well in one of his youtube's, that it's good to end up at the end of a workout or race having breathed roughly the same on both sides. But waves, demand for oxygen etc. make defining a rule difficult.