Schedules often lie by filling every gap. The honest half hour is the block you leave empty on purpose—not because you are lazy, but because you are reserving capacity for the conversation you have not had yet, the errand that will appear, or simply the right to stand up.
When people say they have no time, they sometimes mean they have no slack. Slack is not a reward at the end; it is lubrication in the middle. Without it, every small surprise becomes an emergency.
Try naming one half hour in the week as “unplanned” in your calendar. Not meditation branded, not optimization. Unplanned. If you need to defend it to yourself, remember that machines need idle cycles too.
This is educational writing. Your constraints may make this idea irrelevant, and that is fine.