Your caffeine cutoff should start with bedtime, not somebody else’s lunch break. An eleven pm bedtime and a three pm final coffee are eight hours apart. That is an experiment, not a guarantee.

Include tea, energy drinks and supplements that contain caffeine. Check the serving size on the label. One bottle, one scoop or one café drink can mean very different amounts of caffeine.

The FDA’s commonly quoted four hundred milligram figure for most adults is not a sleep-friendly target. Sensitivity varies, and a total that sounds acceptable does not make late caffeine irrelevant to sleep.

Record the final caffeine time, drinks, bedtime and how the night felt. Add unusual factors such as noise or late work. One good or bad night cannot settle the question on its own.

Move the last caffeinated drink earlier while keeping the rest of the routine familiar. If the drink is really a work break, keep the break and choose a caffeine-free alternative instead.

Look for a repeatable pattern over several nights rather than a perfect score. The full guide below has timing examples and a diary format to help you choose your next sensible adjustment.