Why, for this route
- Direction: 9 hours eastward. Advancing is harder, so a pre-shift pays off most on eastward routes.
- Shift light, not just bedtime — light timing is what moves the clock; the alarm only follows.
- Do not pre-shift more than about 3 days: the gain flattens and the disruption at home starts to cost more than it saves.
- On arrival, Day 1 in Sydney: bright light 07:00–09:00, last caffeine 12:00, sleep 20:00–04:00.