Very good question.
Sometimes, you hear and feel improvement in five minutes – but that, usually, is temporary. Nevertheless, improvement feels fantastic.
This past week, after approximately four or five lessons per student into the school year, I heard solid improvement across the board – in all of my students. Though this speaks to the teacher’s effectiveness, I never assume full responsibility for a student’s progress. The progress can happen only with dedication and sincere intention from the student. So, to all my students, “Bravi!” I’m so proud.
Improvement is tough to gauge on your own. You can’t always hear improvement in your own playing because you are too close, too intimate with your everyday practice. The changes are so subtle to really take notice. A teacher, on the other hand, is the perfect weekly friend to tell you either “Yes, you are going down the right path” or “No, we need to try something else.” So, use your ear and your body for guidance during the week, but don’t get too obsessed about improving immediately. Trust your teacher.