According to Herodotus, the single country of Egypt contained, in his day, a standing army of 120,000 Persians; and, although this was no doubt an exceptional case, Egypt being more prone to revolt than any other satrapy, yet there is abundant evidence that elsewhere, in almost every part of the Empire, large bodies of troops were regularly maintained; troops which are always characterized as "Persians." We may suspect that under the name were included the kindred nation of the Medes, and perhaps some other Arian races, as the Hyrcanians, and the Bactrians, for it is difficult to conceive that such a country as Persia Proper could alone have kept up the military force which the Empire required for its preservation; but to whatever extent the standing army was supplemented from these sources, Persia must still have furnished the bulk of it; and the demands of this service must have absorbed, at the very least, one third if not one half of the adult male population.
For trade and commerce the Persians were wont to express extreme contempt.

The richer classes made it their boast that they neither bought nor sold, being supplied (we must suppose) from their estates, and by their slaves and dependents, with all that they needed for the common purposes of life.

Persians of the middle rank would condescend to buy, but considered it beneath them to sell; while only the very lowest and poorest were actual artisans and traders.

Shops were banished from the more public parts of the towns; and thus such commercial transactions as took place were veiled in what was regarded as a decent obscurity.

The reason assigned for this low estimation of trade was that shopping and bargaining involved the necessity of falsehood.
According to Quintus Curtius, the Persian ladies had the same objection to soil their hands with work that the men had to dirty theirs with commerce.