For the first 9 years of learning the violin, I didn't play any scales or etudes. None of my teachers at the time told me to - I think they probably thought I was doing just fine playing concertos like Tchaikovsky, Mendelssohn, and Bruch. However, it soon became apparent that I was hitting a plateau in my technique. My intonation was not consistent and not improving.

I decided to switch teachers and that's when I was told that in order to improve, I had to play only scales & etudes for 6 months without touching a single piece. Peter Zhang in Sydney was the guy who fixed my technique. Thanks Professor.