Camp followers were not from any select social class. Officers' wives and mistresses accompanied them on the march.

True enough, but the differentiation between the classes (sometimes referring to differing connubial arrangements attributed to them) gave rise to the saying

"Officers and their ladies, sergeants and their wives, men and their women."

If the lass is going out into the world to beg her bread, she'd need her garments to be coloured to appear presentable for longer, as Charley mentions.

Cheers, Rowan