EUREKA - Roman army troops

[Tarbicus]

With the Servian system, each soldier paid a war tax according to his wealth as told by Dionysius. Therefore those who could afford the war tax on the equipment of a class I soldier wore the better armour. In Plutarch (Pompey 45) the treasury income of 340 million is mentioned. There are records of what taxes were paid by a Roman citizen found throughout the primary sources.

So, in a nutshell and practice, the individual paid for the equipment which the state then procured for them. Begs the question, why not just let the men get their own? The reasons I can think of were to guarantee that the individuals would actually be equipped when they went to war, and not spend the money on something else, and perhaps to guarantee the quality of the equipment?