Great question, thanks for asking it. I'm really curious about other replies. Before I had kids, I used to sleep 8...9 hours. I used to not set an alarm, and j

Great question, thanks for asking it. I'm really curious about other replies. Before I had kids, I used to sleep 8...9 hours. I used to not set an alarm, and just let my body figure out when it was time to wake up. I felt I needed about 8h to function well. Since I have kids, I get up before the rest of the family to get some work done (or sometimes, just to decompress and get some alone time). In order to carve out that time, I consciously decided to sleep a bit less. I aim for 7h, but I use "Sleep as Android", which tries to wake me in a light-sleep phase "around" my waking time, so ends up between 6.5h and 7h. Turns out, I can function reasonably well with that. Less than 6h and I'm pretty useless though. I notice I can't concentrate well, but most crucially can't resist the pull of distractions like HN and Reddit. Days after little sleep tend to be lost to procrastination. I've also noticed that I'm becoming less tolerant of little sleep now that I'm nearing 40 years of age.