Decluttering

So here I am, thinking I'm pretty good at de-junking my house and getting rid of things. I try hard not to keep around things I am not using and get rid of stuff on a regular basis. We decided to try and do the navy wide garage sale next weekend and I started to go through the house to get ready. My kids have about 2 million books and I decide to start with those. After going through the first bookshelf FULL of books I only have 7 in the bag. hmm...not good. Each book that I was about to put in the bag I'd somehow pull back out because "Thea will like this later", or "this would be good for a preschool homeschool lesson" or "I paid full price for this and we've barely used it". I'm having a hard time getting past this block. I also found out yesterday that I am the same way with the kids toys. We have SO many and with all the kids they each get out one thing to play with and the house is a mess! I need to simplify but can't bring myself to get rid of the toys. They play with most of them actually, but there are just so many...not to mention I keep buying them at garage sales. Such great, sturdy toys for so cheap...hard to pass up. I'm thinking about putting a limit on myself. Like, "you can only keep as many books as will fit in this small bookshelf." "No more than 3 puzzles per child" "No duplicates of toys"
Knowing that I can always get more books or toys for next to nothing at goodwill or garage sales should give me motivation, but it's still so hard!
OK, I've motivated myself a little...i'm off to try again.