Specifically, the music-education students had practiced an average of 3,420 hours on the violin by the time they were eighteen, the better violin students had practiced an average of 5,301 hours, and the best violin students had practiced an average of 7,410 hours. Nobody had been slacking — even the least accomplished of the students had put in thousands of hours of practice, far more than anyone would have who played the violin just for fun — but these were clearly major differences in practice time.