Setting items in localStorage allows you to store data persistently in the user’s browser, perfect for saving preferences, form data, or application state. As the creator of CoreUI, a widely used open-source UI library, I’ve used localStorage extensively for theme preferences, sidebar state, and user settings persistence. From my expertise, the localStorage.setItem() method is the standard way to store key-value pairs that persist across browser sessions. This approach provides reliable client-side storage that survives page refreshes and browser restarts.