Manturzewska (1990) Identified six stages in the life-span development of professional musicians. Stage 2 is a period of intentional and guided musical development. This is the time when basic technical and performance skills and musical knowledge are learnt. It is also a time where significant changes motivation and inclinations change. There is now a more determined need to play and to learn.
Between ages 6 and 9 the beginnings of technical development occurs with systematic exercises. Between ages 6 and 14 is crucial for efficacy in technical ability and performance. Inadequate instruction or misuse, or too many changes in teacher, will lead to losses in musical achievement, technical efficacy and duration of concert activity in the future.
Manturzewska, M. (1990). A biographical study of the life-span development of professional musicians. Psychology of Music, 18(2), 112-139.