I allow my kids to have 8 - 12 books in each bin. That seems to be enough for a 20 - 30 minute block, but not so many that they can't carry them!
The books are from my classroom library and the school library. At my school each student can check out 2 books from the school library at a time - so often those books end up in their bins.
They have about 5 minutes during Bell Work to change books every day if they want. It is one of the things they do when they walk in the door in the morning.
I do not check their "Work on Writing". I just don't. There isn't enough time in my day to do it.
I do check all of their Writer's Workshop writing though.
