In my opinion, in the 21st century, people live in a sleep-deprived society. Nowadays, many people have sleep disorders. Firstly, we live in times when technology is our everyday life. Access to phones, computers and Internet give us unlimited possibilities but also take us a lot of time. It is often our sleep time. According to scientists, the optimal sleep time is 7-8 hours a day, while people sleep 4-5 hours a day, and they are often sleepy. Secondly, many people suffer from various ailments related to sleep; for example: insomnia, sleepwalking, night terror. Itterrors that can be caused by stress, a lot of light, a lot of travel or shift work. These problems are the most common cause of sleep deprivation. However, from my experience, I know that the number of hours set by scientists is not appropriate for everyone. When I sleep 8 hours, I am as sleepy as if I had slept 5 hours. The optimal sleep time for me is 10 hours. Then I am rested and relaxed.