Full-screen presentation is appropriate when the current task benefits from concentration or needs nearly all available space, such as media playback, camera capture, focused editing, or an immersive activity. Entering that state should have an obvious purpose, and leaving it should be equally clear through a visible control, the platform's standard gesture or keyboard command, and accessible navigation. Preserve unfinished work whenever possible; if dismissal would discard meaningful input, explain the consequence and ask for confirmation. Keep the full-screen workflow bounded so users can remember the context they temporarily left. Routine choices and brief messages generally belong in less disruptive interface elements.