How long to you keep it and how do you get rid of it? How do you explain this to DC (and your hoarding DH, if it applies)?
For example, DD makes houses for her stuffed animals out of diaper boxes, I just saw a post below about making stuff out of big cardboard boxes and keeping it up for a few days, but my family would give me trouble about ever taking it down.
Re: When DC makes stuff out of recycled stuff (?)
I keep things until DD stops playing with them. if/when she notices, I say that the item broke and then DISTRACTION!
I'm a terrible mom and also throw away her art projects, too. She's used to things disappearing, I guess.