This is an update of a looooong ago mod that made AI sims askyou to move in more often. Some people don't even know this is possible. If your sim has a high relationship, a friend might ask them to move into their house. But the default chance of this is only 1%, and only 2% if the relationship is romantic. I've bumped it up to 50% and 100%. Don't worry, they'll only ask once every 3 days.