My daughter is nearly 8, and hasn't seen her father since she was 3.5. That is his choice - he moved overseas to be with a girl.
Prior to this, the arrangement was "you can have her whenever you want her, just give me some notice." His working hours meant that we wouldn't have been able to arrange specific days to be used each week/fortnight/etc. I wasn't working, and she wasn't in school, so it was fine for her to spend whatever time with him he had free (though, being the deadbeat he is, he would often choose to spend his free time without her at all).
I suspect now it would be more difficult if he was still around, as I work, and she attends school, and his industry would pretty much guarantee he would never be free to have her on weekends. I suspect it may be a holidays-only deal, where he had to put in for time off to see her.