The Spoon Theory is a way of thinking about energy. It's based on the idea that everyone has a certain amount of energy that they can use each day. Just like each person only has a certain number of spoons (or other pieces of cutlery) they can use in a day. When your spoons are gone, you have to stop and have a rest.
The Spoon Theory can help you think about how you plan your day - if you know you've got a certain number of spoons to spend, you can decide which activities to do with that amount of energy and save the more difficult tasks for when you have more spoons. People with chronic illness or disabilities might feel like they have less spoons because they experience more symptoms or fatigue compared to people who don't have those conditions.