I can't remember with ds when he stopped waking up and pretty much slept through like clockwork. He is 7 now and rarely wakes up unless it is a nightmare.
DD however is another story she wakes at least once a night approximately 3-4 nights a week. She has just turned three and wakes very distressed but can't tell us what is the problem. She will go back to sleep with a bit of a cuddle and a song but very much looking forward to when she will reliably go right through. Some nights she will wake 2-3 times usually before midnight.