I've had NO problem telling a mooching relative that wanted to move in again "NO!". Not a shred of guilt here! Told her that she needed to go home to her mother! Strange how she worked it out and came up with her own place. I have learned my lesson, and will not be repeating it again. People only use you if you let them. You'd be surprise at how resilient they can be when they find out you are not going to play into their game.