I don't purposely keep all of the things, but somehow the disney stuff gets stashed in folders or boxes or drawers. However, as I find it I tend to toss it out (even the room keys). However, DP has every WDW ticket he's gotten in his wallet.
I do need to go thru closets, cupboards, drawers, and the many many boxes up in the attic (and out in the garage) and start tossing things. When I got home to my mom's house (as she's trying to clean out all the "kids" stuff) I see things that I left there and she tells me to take home. I usually tell her to just toss it (old stuffed animals, etc). But, in one of the boxes she recently sent home with me I found some old Columbia Harbour House cups. I think it's a series of cups and I have 3 of 4... so not sure why I kept them, but I did. They'll likely end up in the trash (or in the donation box).