According to Time magazine (subscription required), by the time children turn 18, they’ve spent only 13% of their lives in the classroom. So for all the hand-wringing over schools and teachers and getting your kids in the right classes–and eventually colleges–I think it’s fair to say that a huge chunk of children’s development depends on what they do outside the classroom. As important as school is, that after school job, sport, club, or just plain sitting around and watching TV may impact kids more.