The onset of disease is a progressive process. Medical science usually divides the process of disease development and regression into four periods: the susceptible period; the preclinical period; the clinical period; and the recovery or deterioration period. In many cases, the process of disease development and regression is reversible; the key is how early the disease is detected. When we understand the process of health and disease, it is easy to understand why medical professionals always see “health checkups” as an alarm for disease. For individuals, regular health checkups enable us to detect early signs of certain diseases and give timely adjustment and treatment; at the same time, health checkups can observe the functional response of important organs in the body and give necessary improvements at the right time. Through health checkups, individuals can strengthen their understanding of their health status, change bad habits and avoid risk factors, which is conducive to long-term health maintenance. For the society as a whole, the benefits of regular medical checkups are even greater, for the early detection, diagnosis and treatment of diseases, as well as the prevention of the occurrence and development of diseases through the regulation of sub-healthy states, all of which save health resources and maximize and rationalize the use of health resources.