I was amused to read in a footnote to a chapter on the art and teaching of Artur Schnabel that a colleague of mine chastised Schnabel in no uncertain terms (in print, not face to face) for recommending that piano students not practice so much. Schnabel maintained that he did most of his preparation while going for walks.
I tell my young students not to practice and, if they do, to tell somebody else. Of course, I can tell right away that they have or haven't practiced. What is more important than practicing is dreaming about music, any music. Internalizing is really difficult. Getting the external music to match the internal is the work of a lifetime -- work worthy of a lifetime. Putting the emphasis on the external aspects (i.e., technique), especially at an early age, merely fogs the issue.