Teaching is part of the learning experience. Our Sensei encourages teaching. From my experience, when one is teaching, one will discover one's strength and weaknesses.
The senior students actually have the obligation to show the correct way of doing things. Even though this would be considered disrespectful in classic budo, in modern budo this is actually encouraged, just as long as the correct way is shown.
Being able to teach what one knows actually proves that one can accept responsibility for what one has learned. But in teaching one must not have the "I'm right, you're wrong" attitude. This arrogance will teach nothing, and only bring downfall to the one who teaches. The correct attitude in teaching is "This is what I've learned, let's discuss this together, there are probably things that you could teach me". This humbleness will teach you even more about what you're teaching.
From my experience, teaching has shown me how inadequate I am in the knowledge that I am teaching and motivated me to learn even further. With the teaching process, one will discover weaknesses. And with the correct attitude given to the students and given by the students, these weaknesses could be covered.
When one teaches, one does not only teach others, but also teaches oneself. Learning by teaching, teaching by learning.