Why did people join the roman army?
It depends on the period of Roman history you are looking at. During the Republic (500 BCE until 44 BCE) soldiers were drafted from the citizens of the republic who met a certain property qualification (mostly middle-class farmers). This starts to change with the Marian reforms in 107 BCE where Marius takes volunteers who don’t meet the property requirement. This is where the recruitment changes and men now join the army exclusively for pay and booty. Men are still conscripted until the first decades of the empire (20s CE) but it is mainly lower-class volunteers.