Forts save you money!!!???

[Sitalkes]

Well I just had one of those "ARRGH! How long have I been playing this game and I never noticed this!" moments - I started a new Britannia campaign as the Welsh and noticed that there are a lot of forts. I never bothered much with forts as if you build one you might be providing a base for your opponent, and it requires a family member to build one, and the money could be better used elsewhere BUT now I see that up to three units in a fort do not pay upkeep - any unit, even bodyguards!! Most often it is two units, but sometimes it seems that three will have free upkeep. So if you build a chain of forts one move appart you could save some serious money and the forts probably could pay for themselves within one turn!! Is this just a feature of the Britannia campaign? Do other players use forts much and if so, why?

[Surgeon]

I believe it's a feature of stone forts in general. I don't recall exactly if this applies to the Crusades campaign but I think I remember getting free upkeep there, too. Wooden forts didn't save me any money.