[ICAL_Pete]

I can only speak from our experience as TEFL course providers. We have many English teachers who come to us for a refresher course or simply to challenge their knowledge further, learn new techniques and open up to new ideas.

The feedback we get from seasoned teachers is that there is always something new to learn and taking a course forces them to sit down and actually seriously think about new approaches. They find that the one to one exchange with our qualified and experienced teacher trainers who are active on the field - so to speak, is very helpful in getting them out of a staid mindset.

Of course a lot depends on the type of course one takes but overall I'd say challenging oneself within a formal educational setting like a teacher training course does help one improve their teaching skills.