As I always say, sex (with a girl or on my own) should be my first and my last job of the day!
In the morning just one time is ok. Not more (at least before breakfast!) or I feel quite tired or "empty" in the rest of the morning!
I also think before every lunch and dinner... and, obviously, late in the afternoon and in the night..
Finally: 1 time when I wake up, 1 before lunch, 2 in the late afternoon, 1 or 2 in the night... this would be my perfect day!!!
My gf says I'm quite horny.. we have great sex, but she's always more tired than me. Mmm, now that I think I have never found a girl who makes me say "stop, it's enough!"....