The save file size keeps fluctuating
I'll start by saying that I'm not the only one who has encountered this problem, but I haven't found any discussions about it online. My save file doesn't weigh that much - or rather, it didn't weigh very much. At some point, it ballooned to 50 MB, even though I hadn't done anything. Blaming it on characters from the Gallery (even though they couldn't possibly weigh 30 MB...), I deleted them. The file size dropped back to the original, but later it grew again.
Then I started blaming it on the fact that I had built up the world. After deleting all the lots, I noticed the size dropped, but only to 30 MB instead of the original 25. After playing for a bit, I saw that the save grew back to 50 MB (while I literally did nothing at all). Later, I moved in a new family and placed a house for them - and the size dropped to 30 MB.
JUST TO CLARIFY RIGHT AWAY: this happens even without mods, and in a completely clean vanilla save; mods are definitely not the issue here.
So, has anyone encountered this problem or seen a discussion about it? Or maybe someone actually knows a solution? It's just scary that this happens even in new saves and without mods, but the reasons are unknown. I just want to play the game without constantly worrying about why the file size keeps jumping around