At one point, (I think she was 6 at the time) we put everything except DD's books and clothes into trashbags because she would not pick up her room or do anything else we asked her to do around the house. We really thought this would do the trick. Well she showed us...we had those trashbags in our front room just waiting on her to comply for over 3 months. She would talk her sister into playing with her just so she would have some toys to play with and I honestly don't think she really missed anything we took. When I told her she had 3 days to get it together or everything was going to a garage sale she still didn't seem to care. I finally ended up getting rid of most of her stuff and sticking some of the good stuff (things I couldn't part with) in a storage tub for a later date. I remember thinking as I put the things in the tub that neither of our daughters truly treasure a lot of the material things we (and grandparents) have bought for them, so maybe we need to re-evaluate what really matters.
