If you wake in the middle of the night "for no reason," you might be spending more time in bed than your body has sleep to fill. Two numbers from any sleep tracker will tell you. (Apple Watch, Eight Sleep, Oura, Fitbit — use 30-day averages if you have them.)
The complete "Find Your Real Sleep Window" guide — the same experiment our founder ran on his own tracker — comes with the weekly Restful Routine letter: one honest lever per week, our tracker experiments, and what not to buy. And if you haven't yet, take the 2-minute Sleep Assessment; it may tell you to buy nothing at all.
Consumer trackers are estimates, not lab studies — treat these numbers as directional. This is education, not medical advice or a diagnosis. If you've had months of bad sleep that affect your days, the gold-standard treatment is CBT-I — ask your doctor. Never restrict your sleep window below 6½ hours, and don't drive drowsy.