Caffeine can linger
Caffeine affects people differently, and its effects may continue longer than expected. Rather than assuming a fixed cutoff works for everyone, notice how timing connects to your own bedtime.
Run a calm experiment
For one week, keep your usual amount but move the last caffeinated drink earlier. Note your wind-down and how long it feels like it takes to fall asleep, without obsessing over a score.
Keep context in view
Stress, travel, illness, and schedule changes can all affect sleep too. One adjustment is useful data, not proof of a single cause.
