As children grow, they are generally subject to a formal education. Many of them look forward to graduation, and they vow to never be caught in a classroom again. It is a natural part of the ageing process, and they often feel restricted by the rules and limitations imposed by both parents and the school system. They look forward to the freedom from tests and assignments, but many of them will continue to learn long after they have graduated. Learning is a lifetime process, and it seldom depends upon books, teachers or classrooms. Students in the more advanced grades are taught this, but those who leave school at the first opportunity will only discover it through trial and error.