It's totally up to you! You can keep your set for as long as you like, or you can return your set as often as you'd like; you'll be billed the same monthly rate either way.
To refresh your set, simply put your Rocksbox with all pieces you don't wish to purchase in the mail using the reusable envelope and pre-paid return shipping label that came in your set.
All pieces that you don't wish to purchase must be returned at the same time. For any pieces you'd like to buy, simply keep them! We'll charge your card on file when the rest of your set arrives at our warehouse.