Re: When to introduce breakfalls
Just as Peter, ukemi are the first thing we teach to beginners. We practice break falling at the start of all sessions, just after the warm up. Sometimes we do a few, sometimes we do a lot. It all depends on who's teaching.
At the end of their first session, beginners are asked to do randori (a very cut down version and we are careful) in which the two main things are: Avoid and Break fall.
Oh, break falls are on the first grading where they have to perform all of them from standing. This grading is generally taken in the first 3 months.