Rest gets sold as indulgence, which might rank as civilisation’s most expensive misunderstanding. Rest controls attention the way maintenance controls machinery. Skip it, and the system still runs, briefly, and then it grinds. Short breaks reset vigilance. Sleep steadies mood and judgement, and judgement protects focus from cheap distractions. A tired brain grabs the loudest stimulus because it can’t afford expensive thinking. A ten-minute break with movement and daylight can restore the ability to hold a complex idea in mind. This looks like discipline from the outside. It’s responsiveness. Notice the signal. Adjust early.