Sleep is crucial for maintaining good health. Lack of sleep can lead to various diseases such as eye diseases, hepatobiliary disease, emotional disorders, cardiovascular diseases, and lung diseases. The best time to sleep is between 21:00 to 3:00 as it helps protect and nurse the liver and gallbladder. Staying up late can cause liver deficiency, blurred vision, presbyopia, and other symptoms. It can also lead to emotional anxiety disorder, depression, and even suicide. Therefore, it is important to prioritize sleep for a healthy life.