Player/Characters must pay Gold Pieces equal to 1% their experience points for support and upkeep, until such time as they build a stronghold. If the stronghold is in a wilderness area all support and upkeep costs then cease, but if it is in a village or town not controlled by the player/character then support and upkeep must continue.As a principle, I like the idea of "encouraging" characters to settle down and establish a stronghold in the wilderness. Unfortunately, this section of Volume 3 is unclear. How often must a character pay these costs? Once per month? Once per year? Likewise, is it all characters, from level 1 on up or only characters of a certain level or higher? I presume the former, but the text is silent on this point.
Regardless, it's a rule I haven't been applying in my current Dwimmermount campaign and I doubt I will retroactively employ, but I'll certainly keep it in mind should I ever start a new OD&D campaign -- once I figure out exactly what the rule is saying, that is.