This should consume 10 minutes at most. Your child reaps several things from this post-lesson review. It is a tangible reminder that you support his efforts and are vitally interested in the content of what he is doing. Ideally, both Mother and Father sit down with the child to preview the upcoming week's activities, but in the real world a consistent commitment from one parent is sufficient. It doesn't have to be the same parent each time, either.
Most students benefit from a consistent piano practice time.
I tell all my students that schoolwork is first priority. If there is a large assignment that evening, there may be no time for practice because schoolwork is most important. After schoolwork comes piano playing, however. When that is complete, then there's time to play outside, use the telephone, watch TV, or whatever else they'd like to do. It's important that children know that piano study falls right under schoolwork in the day's hierarchy.