I also have a secret third hand.
I quite like my MIL - in moderate doses. Three days would be lovely. Five days is tolerable. NO guest whatsoever is welcome is our house for nine days: we need some space and privacy. My DH travels about 60% of the time, he leaves again on 6th January and our couple time is precious. I had organised for the kids to go somewhere else for a few days so that we could cuddle up and get to know each other again. To add to that that on the first time in two decade we can go out to a new year party on our own and maybe you can understand why I felt a trifle miffed with DH.
Last year MIL stayed for two and a half weeks and by the end we had agreed never ever EVER again. Even DH had told her to shut up. To spend more than a few days with a guest who constantly criticises everything you do, your house, your children, the way you live, and who never stops talking, follows you everywhere, interfering in housework, breaking things, was so irritating we considered changing the locks. W tried organising for her to go out with my mother, shopping, to a pretty town nearby, to give us a break. My DM brought her back after an hour, saying she couldn't take any mOre criticism of me and the children. He then tried taking her to visit HIS ex whom she knew. Ex also insisted she leave early because if constant criticism of me,children, her children, our house, life, the universe and everything.
So we made a pact. We would invite her for Christmas, organise theatre trips, take her out to dinner, take her shopping, take her to France for a few days, and make it clear, right form September onwards, that we wanted time to ourselves over new year and would therefore be taking her home before then. She said she would go on a cruise.
Well, that didn't happen, and she has been ringing me to say that she hasn't got anything planned, and he's all she's got etc. when she didn't get an invite from me, she rang DH and pressured him and he caved.and frankly, if he had been on the room at the time, I would probably have hit him. He is coming home today and has agreed he will ring her and explain there has been a misunderstanding and that I had already organised something so she can't stay.