Judging from the military service system in various countries in the world, there are two main types in the world today:
One is the voluntary military service system, also known as the conscription system. This system is that citizens should voluntarily enlist in the army and sign service contracts with the army. This military service system is more suitable for countries with relatively developed economy, large population, sufficient sources of military personnel recruitment, good surrounding security environment and basically no direct military threat. Its advantages are that soldiers become a social occupation, have a relatively long service time, can get relatively full and systematic training, have a generally high quality of individual soldiers, and have a strong overall combat capability of the army. Therefore, the number and scale of its standing army are generally small. At present, Britain, France, Australia, Germany, Canada and other western developed countries mostly adopt this military service system.
The other is called compulsory military service system, also called conscription system. This system is that the state forces citizens to perform military service for a certain period of time within a certain age range through laws. This military service system is more suitable for countries with small population, difficult to maintain a standing army of a certain scale, or weak economy, complex surrounding security environment and public order, or even a greater direct military threat, or a large territory, which needs to maintain a standing army with a relatively large number and scale. The advantages of this military service system are: first, the state can maintain a large-scale standing army with less investment. Second, the high proportion of nationals who have served in military service is conducive to national defense mobilization in wartime. For example, Switzerland, Sweden, Norway and other Nordic countries, although economically developed, do not need and cannot maintain a relatively large standing army in peacetime because of their small land area and small population. Therefore, the adoption of compulsory military service system can not only keep the standing army in a small scale, but also enable most citizens to receive professional military training, thus ensuring the rapid mobilization and expansion of the army in wartime. As an underdeveloped country, North Korea poses a great threat to national security. Due to the compulsory military service system, a large-scale standing army can be maintained with limited economic strength.
However, China and Russia need to improve their combat effectiveness and maintain a certain military scale because of their large territory and complex surrounding security environment. So at present, the military service system is a combination of voluntary military service and compulsory military service, based on conscripts and with professional soldiers as the backbone.
In addition, India's military service system is quite special. The Indian army originated from the British colonial army before independence. After independence, it completely inherited the British military service system and adopted the recruitment system. However, due to the obvious caste differentiation in India, internal ethnic contradictions are prominent. Therefore, although conscription is also claimed to be geared to the whole people, in order to maintain the stability of its army, India's soldiers usually come from its high-caste ethnic group and have obvious hereditary characteristics.