You might want to start a thread of your own for this, speki4eyes. There's a 'start a new discussion' button at the top of each of the forums.
I know what you mean - when mine leave there is always a lot of clearing up and it feels like very little thanks. I usually find that my fancy bath oil has taken a hammering too . But the other way to look at it is that they see your house as their home, even though you may now see it as (finally) yours again. They are just behaving as though they had never left, and in many ways that's quite a good feeling. They know they are welcome, and don't see themselves as guests.
Last weekend, in Rutland, the first statue in Britain of the late Elizabeth II was unveiled.