Keep a sleep diary you can use.

Going to bed, trying to sleep and falling asleep are different events. If you only know when you went to bed and got up, call the interval time in bed. Do not subtract an invented number for awakenings to produce a precise sleep total. An approximate answer with an honest label is more useful than an exact-looking guess.

For a wearable entry, note the source and leave the recorded duration separate from your estimate. Use the same convention across the diary. A late bedtime that crosses midnight still belongs to the following morning's entry. These small choices prevent confusing duplicates and make it easier to compare a baseline week with a later habit change.

Public sleep diaries can include caffeine, alcohol, naps, exercise and medicines as context for a professional discussion. The NIH provides a free printable diary linked in the sources. You do not need to copy every possible field into a personal habit experiment; begin with the information that helps explain the question you are asking.

If you are observing an earlier caffeine cutoff, record the last caffeinated drink and whether you followed your plan. Add a short note for illness, travel or a very unusual workday. Avoid writing private details you do not need. A small, purposeful record is easier to maintain and easier to share selectively if you seek advice.

Complete the morning answer while the experience is still fresh. If you miss it, mark it missing. A rating reconstructed after seeing a week's graph is influenced by information you did not have that morning. Do not copy the previous day's value just to keep a continuous line, and do not treat a missing answer as your lowest score.

If you remember only part of the night, save only that part. For example, a reliable final wake time does not require you to invent a bedtime. Keep corrections identifiable in your own notes. The aim is a record you can trust, not an unbroken streak that hides where the information came from.

At the end of the planned period, look at the range of mornings as well as the average. Note whether the better or worse days align with the habit you followed, weekends or a change in circumstances. One memorable night can dominate your impression of a week even when most of the entries tell a quieter story.

Write a short result in ordinary language: what changed, how many mornings you recorded and what remains unclear. If the baseline was a holiday and the experiment was a stressful work week, say so. A diary helps organize observations; it does not remove those differences or prove that one habit caused the outcome.

You might keep a practical habit, try the same question in a more typical period or bring the record to a clinician. There is no obligation to add another field just because the answer is uncertain. When persistent sleep problems or daytime sleepiness affect your life, the next step is professional advice rather than a longer self-directed experiment.

Night Lab's planned morning check-in keeps a rested rating central and makes other context optional. Its first public release is pending. Until then, paper works. A calm, consistent record can help you ask a more specific question without waiting for a new app, wearable or subscription.