Why do you need 8 hours of sleep?

You need sleep because the longer you stay up, the less you will be able to concentrate. And if you go to bed late then you are likely to oversleep in the morning and you wont be able to concentrate. You need to know what your sleep time is because your doing it for your own health.

When they say beauty sleep they are true because if you dont sleep then you get rings and bags underneath your eyes and that can make your face look a bit worrying to others.

Sleep loss can affect the mood that you are in.

However not everyone has the same sleep requirements. Some need more than others. 8 hours is considered an average.