Once the time spent waiting and riding the bus, after school activities, homework, and time with friends it is taken into consideration it is likely closer to 8 ( minimum) to 10 or 12 hours that school rules a child's life.
Also, considering the time a child needs to play, simply to have time alone, and **sleep**, parents really have little time ( proportionally) to impact a child's school day.
Any dilligent parent can do it. I’m nothing special and I managed.