Upkeep costs

James Maliszewski posted about OD&D support and upkeep costs. I had been wondering about the frequency of payments myself, and assumed that upkeep was paid on a recurring basis. As migellito says in the comments to James' post, paying upkeep costs at the time XP is awarded is the most parsimonious interpretation, and therefore the most appealing to me. That works to simply bookkeeping for food, lodging, maintenance, etc. If, on the other hand, the referee wants to use upkeep costs as a stick to drive characters toward play focused on establishing and maintaining baronies, upkeep fees should be assessed more frequently, perhaps on a weekly or monthly basis.