How Long Do You Keep Your Kid’s Art

I now have four kids, and the creative masterpieces adorning the fridge and overflowing the drawers is already becoming too much!  Some of the art is great or cute but a lot of it is...well, good practice for the kids :)  About once a month we have the kids go through their art and they get to keep a few of their favorite pictures and we have them throw out the rest.  I know it seems like we are stifling our kids self esteem that their art doesn't matter - but in 5 years are they going to care about the 30th picture of Bumblebee they colored?  So far, they seem to understand that it is better, because they can find stuff easier if it isn't surrounded by hundreds of colored papers...I hope it stays that way.  Here is another story similar to mine about another family who has the same dilemma.