Spoon Theory is a metaphor used to describe the mental and physical energy people with chronic illness or disabilities have in a given day. The "spoons" represent the energy you have for various tasks, and when you're out of spoons, you're out of energy.
Each task you perform consumes a certain number of spoons. At the end of the day, if you've used all your spoons, you might not have enough energy left to complete additional tasks, and you could experience "spoon debt."