Same here. very light sleeper and just get up when I need to. I do wear my watch to bed(it tracks sleep rythms I guess) so I just check it when I wake up multiple times at night. And no it's not just because I am old. Ive been that way as long as I can remember. Ive probably woken up to an alarm a handful of times in the last 20 years. I don't even set mine anymore. My wife is the same. sleeps like the dead.I haven't needed or used any type alarm for something like 25 years. Don't ask me to explain it. If I go to bed knowing I need to wake up at 4:00, that's when I'll wake up. Same with any other time. Drives my alarm-dependent wife nuts. When it's time to wake up / get up, that's exactly what I do. Out of bed or out of the sleeping bag immediately and start getting ready for the day.