If once he has got the right fingering, plays in good time, with the notes fairly correct, then only pull him up about the rendering; and when he has arrived at that stage, don’t let him stop for the sake of small faults, but point them out to him when he has played the piece through. . . I have always adopted this plan; it soon forms musicians which, after all, is one of the first aims of art and it gives less trouble both to master and pupil.
Ludwig van Beethoven
mistakes, mistakes-in-practice, music-teaching, teaching