When pupils reach adulthood and obtain full-time employment, they should anticipate to work for around 8 hours every day. Spending 7 hours at school will offer pupils a decent idea of what it would be like to spend 8 hours a day at work. However, since people have different levels of physical and mental endurance, the ideal length of the school day may vary from person to person. In ancient times, when people lived in small communities and had little access to education, the length of the school day was about 10 hours. Today, with most people living in large cities where there are many opportunities to learn new things, the average length of the school day is only 5 or 6 hours. The reason why schools today are so short is because children cannot handle any more time at school. In the early days of education, when schools were not organized on a daily basis but instead went for several months at a time, the young students would need more sleep then. So their teachers would let them out of school at noon every day so they could go home and sleep for about three hours before starting work again. Nowadays, this is no longer necessary because kids can stay in school for eight hours at a time and still get all the attention they need from their teachers.