Summary:
Someone may be motivated to enlist in the armed forces because they need the money, because of pride, or because they were directly forced to.
Explanation and Details:
Numerous factors can motivate someone to enlist in the armed forces.
Material necessities and benefits:
Typically, enlistment in the armed forces offers good or decent pay, as well as room and board (housing and food). Some people may need the money for their families. For people who don't have access to higher education (university or college), other jobs may not pay as well.
Pride and Desire:
The armed forces offers opportunities to rise among the ranks and earn respect. In many places, being in the armed forces is considered a respectful position. Some people may also dream of being a "hero" when they return home. Others may enlist for a specific cause that the armed forces are defending, for example, in peacekeeping.
Forced/Conscription:
In some oppressive governments, it is required for someone to enlist in the armed forces. This is also known as conscription. When the government either wants or needs more people in the military, they will make it mandatory for everyone, or a certain group of people, enlist.
If they do not enlist, they may be punished or face public humiliation.