I have map maintenance nearly every time I zoom in from the world map. Just now when I started the game and loaded the file, 1) I had to do map maintenance immediately, before it would even display the village I was in, then 2) again on zooming out, which was weird, then 3) I took a few steps on the world map and had to do maintenance again on zooming in.
I'm playing URW ver 3.40 (stable), with Shaman Mod 3.42. Running Windows 8 under Windows 7 compatibility mode. I'm approaching the end of year 2, waging a campaign of genocide against the Njerps until I find a hunting horn, so lots of junk on the ground. I did lose some things to the item limit bug, in case that's relevant.