Techniques

Short focus rounds with short breaks, and a longer break every few rounds.

52 minutes of focus, then a proper 17 minute break.

Two or three deep blocks of about 90 minutes, each followed by real recovery.

Study for about 50 minutes, then watch one episode as the break.

For long days at a screen: every 20 minutes, look at something 20 feet away for 20 seconds.

For long working days: a quiet nudge to drink some water every 45 minutes.

For long sitting days: every 30 minutes, stand up and stretch for a minute.

Focus until it fades instead of stopping at a fixed time, then take a break.