Re: teachers can no longer study?
Just for myself I'll demonstrate techniques but then I find it even more important to take ukemi from the students to make sure they're doing it right. Push them a bit, find their limits and make them bang against them. Then it's my turn to do it a few times too. And I want them to challenge me as well. Learning never stops.
I also make a point of taking other classes whenever possible. And I've been known to show up for general practices and just practice.
And lately I've spent a lot of time at home practicing on my own. One benefit of being an IS/IP convert is that there's lots of work to do on your own -- no one else required. So I count it all as training.