While I was packing, the kids near drove me into a Home for the Bewildered, with questions...
"*GASP!* Are you packing my toy/blankets/shoes/crayons??????????"
"NOOOOOOOOO. Mum, I neeeeeeeeeeeed that toy/book/game for toddlers that I haven't looked at in 3 years. Don't THROW IT AWAY."
The day we moved, we took the kids to school as usual, from the old house, and picked them up as usual, and drove them to the new house. There they found their beds made up, their bookshelves assembled, and their desks waiting.
It was all very exciting for them. (although we were frankly too knackered to caper much)
Over the next 2 days, I slowly unpacked all the clothes, toys, books etc. And each day, when they encountered more of their stuff, they cooed over items that they hadn't seen for, at most, 2 weeks.
The familiar had become new again by being presented in a new situation.
It was quite amusing to watch. Until I realised that I was doing THE SAME THING!
The Princess in particular went crazy, insisting that all her soft toys be in bed with her, because they are all special, which is all very well until you see how many she has.
Oddly, though, when she saw some of her stuff in the new room, she said, "You can give that away, Mum." Seems it had lost it's appeal somehow.
And .... I DID THE SAME THING!
So there you go! the trick to combating hoarding is apparently to move house.
Too easy, mate.