As in, when I can't think of which new project to start or what I want to do next, I prepare. I put glitter on flowers that will get used eventually, I paint chipboard in at least a base coat, I make fabric buttons. The key is to get in that studio and make something. It doesn't need a home or a specific place just yet. It does mean that when I am ready to work, I have supplies. I don't need to wait for anything to dry. At the very worst of a bit of creative block, it can unblock you and get you working on bigger projects.
This sweet little card is made from left over stickers. Almost entirely. I just made a vellum sun and coated it in glitter. Update old supplies by add and/or subtracting something from them. Take the supply and put it into a new context.