My kids should answer this question for me, since they are the ones who decide when I get to sleep...
But 3-4 hours a day sounds about right.
@Tarzan How old? It seems there is almost no effect.Before I had my kid: 22-6 week, 23-8 week-end
Since I have my kid: 22-6 week, 23-6 week-end
For me, before children, if nothing had to be finished or no time with my wife, while she was in China, mostly 22/23-6. Very rarely after 1 am, because then I get a headache the next day. I need 6 hours, a little more on weekends.
Now, weekends don't matter and it usually is 2-5 hours per night, rarely ca. 6. But with 1-3 breaks of different lengths. My 2-year-old daughter likes to go to sleep between 22 and 23 (while I hold her for a long time), and get up between 8 and 9, but I have to get up at 7 the latest. Can be 4:30 sometimes too, though. There is no clear schedule.
So it all depends, but if it's 6 h with max 1 break, then I'm satisfied.
If several nights with less than 5 h follow each other, it affects me a lot, but I can't do much about it.