Time Is Not Equal
Published research on ultradian rhythms suggests that focus levels may shift every 90 to 120 minutes for many people. Scheduling demanding work during a natural dip can mean rework later. Mapping tasks to alertness instead of clock slots may reduce friction and decision fatigue for some individuals.
Some people find that shifting two high-focus blocks to their personal peak window frees up evening hours without adding total work time. Results vary by person and are not guaranteed.