“The Spoon Theory”, a personal story by Christine Miserandino, is popular among many people dealing with chronic illness. It describes perfectly this idea of limited energy, using “spoons” as a unit of energy. - from Healthline
”Spoon theory is a metaphor that is used to describe the amount of mental or physical energy a person has available for daily activities and tasks. It was developed by Christine Miserandino in 2003 as a way to express how it felt to have lupus. She used spoons to provide a visual representation of units of energy that a person might have and how chronic illness forces her to plan out her days and actions in advance, so as not to run out of energy, or spoons, before the end of the day. It has since been applied to other phenomena, such as other disabilities, mental health issues, marginalization, and other factors that might place an extra – often unseen – burden on some individuals.” - Wikipedia page for Spoon Theory