I think in this case we know enough about biology to not even have to say "everyone is different" - regular exercise and regular wake times, combined with no alcohol, help anyone's sleep.
It’s amazing to hear when someone makes positive lifestyle changes, sticks with them, and then reaps the benefits over time.
I always do my best to be supportive and encouraging when I hear people tell me about it in person, but I’m also amazed at how people talk about their lifestyles prior to some of these changes as if it was normal. I’ve heard multiple stories of people cutting out alcohol, which after some probing revealed that they were drinking at least 5 nights a week and often multiple drinks (by the medical definition of units of alcohol, not just number of physical containers) per night.
It’s common sense that changing these lifestyle habits will provide benefits over months and years, but I guess when you’re in the middle of those habits and some people around you are doing the same then it can feel normal.
If I've been dry for ~ a week, I'll notice sleep degradation around two beers drank <4 hours before going to bed.
If I've been in a groove of going out, the limit is higher.
It’s about lifestyle changes and adaptation to those changes over long periods.