We don't have a schedule for rotating Caspar's books, toys or materials. He is old enough now that he will change things around on his own or ask for assistance. Christmas, birthday or any other time he receives something new is always a good time to rotate or shift things. Otis's materials are very different. I intentionally rotate these often, sometimes weekly.
Our storage cupboard contains mostly Caspar's materials. Otis's things are generally stored in his room. This cupboard is never really tidy so lots of baskets work well for me. Caspar can reach and has access to the bottom two shelves.
We like to keep our books in four different sections; fiction, non-fiction, early readers and board books. This is important to us right now. Caspar loves early readers. He can read some of these books by himself from guessing the words or from memory. It's great having easy access to board books for Otis who cannot be trusted with paper pages.
Easy, simple storage.