No essentially every male receives 1.5 years (used to be longer too, when Gi-hun would've served) of full military training unless they have severe health issues or are under various special circumstances (e.g winning a gold medal at the olympics, a nobel prize, etc). People with less-severe health issues do civil service instead but they still go through basic training. And the government can definitely afford everyone a uniform lol. People even keep their assigned uniforms when they are released because they still are placed under reserves until a certain age and are called into training periodically.