Assuming we're talking purely about longer distance swimming (100m+), billateral breathing is my preferred breathing pattern. However, my [very good] TI coach tells me that breathing every stroke cycle to one side only (i.e. every time the left arm recovers, you breathe; then swap after a length to the right etc) is the best way to swim. Apparently it's been scientifically proven that the advantages of more regular intake of air outweight the disadvantages of breaking one's streamlining slightly. In addition, when one breathes to a 'new' side, the head is inclined to lift higher, whereas after two or three breaths to one side you become better at it (short term muscle memory).
Can anyone comment on either of these points? Terry often says in his videos that with swimming often the best thing to do doesn't feel natural at first, and it instead it takes hard work to achieve. Billateral is natural to me, but what I prefer as a novice is of no interest to me - I want to do the best thing. I trust my coach, obviously, so will do what she says, but in the meantime I'd be interested in people's comments on the two things I've mentioned above.