As for equipment upkeep, I feel that equipment prices should not be paid only once, mainly for game balance reasons.

However, game balance aside, we could well imagine that plate would require a higher upkeep costs than leather, and what to think about mounts… Would a 1st lvl warrior with light warhorse, steel shield, sword and plate make ends meet by begging at the side of the street, while the simple pikeman lives like a king.

There should be a cost for equipment to the regent, either in increased pay or in an upkeep cost. The upkeep cost should be based on the price in the PHB because these prices are already balanced. I took an arbitrary 1/10 of the PHB price mainly because of easy calculation. Moreover this means that muster and yearly upkeep costs are equal when the equipment costs are half the unit’s quarterly pay. (lvl 1 war. 100gpof equipment; lvl 2 war. 250 gp)

I am not sure whether this is best and would gladly hear of better ways.