Your list is a perfect subset of mine. Transitioning into no caffeine has revolutionized my sleep and productivity. One additional point that has really helped me a lot is realizing that I should never eat anything within 2 hours of bed time. It took me a while to connect the dots on my waking up at 12-1am back to having had eaten half a pizza at 9pm. Anything with a delayed action like that is very tricky to keep an eye on. This is the principal reason I dropped the caffeine. The effects/side-effects just became too unpredictable.

Caffeine is too useful for me to give up entirely. I had similar success with a rule: no caffeine after 12 PM (not even caffeinated soft drinks). Caffeine has a long half-life, which is especially problematic for people who, for genetic reasons, respond more to a given amount of caffeine. What I usually do is I have 2 cups of coffee back to back before 11 A.M. I feel the benefits for most of the day. It may be tempting to violate the rule and have an afternoon coffee “just this once” at the beginning but you get used to it. Furthermore, if you feel the need for more coffee in the afternoon, that’s a sign that your work habits and distractions need to change, not your physical energy level.

> if you feel the need for more coffee in the afternoon, that’s a sign that your work habits and distractions need to change, not your physical energy level.

Out of curiosity, why does this apply to the afternoon coffee and not the morning coffee? Maybe finding coffee useful at all is a sign?

Because cafeine breaks down over time so your evening/afternoon coffee has a much bigger effect on your later sleeping attempts than morning coffee. I don't drink coffee at all so that does not apply to me but I can see the confusion in the GP and your response to it.

Correct, that's what I was referring to with the long half-life. The later you consume caffeine, the more likely it is to disrupt your sleep. A logical extension of that is the following: if you know that caffeine has a worse reward-to-harm ratio in the afternoon, and you consume it even though it might disrupt your sleep (assuming it does), you might be grasping for productivity straws. Alternatively, caffeine pretty much only has upside when it is consumed in the morning. It increases wakefulness and several academic studies found that coffee specifically improves your health (not sure how much of that is due to the plant material vs. the caffeine).

For those who cannot or would not give up caffeine, consider that the reason you wake up prematurely is because you're going through withdrawals. When I started having my last cup in the late afternoon I started waking up too early less often.

This is pretty much me. But less focus on sunlight and more focus on sleeping at the same time.

Also exercise helps.