I have never had a problem sleeping. Even with a 1-1.5 hour nap each day.
Last summer I did cut out all caffiene and my sleep is a ton better. So is my energy all day too. No more Diet Cokes, pre workout supps, etc.. When I sleep it is more restful. But then again, when I was on the caff-jig, I never had problems being tired the next day or falling asleep.
I only use ambien for long plane rides.