my vice is caffine...i have cut down a fair bit, used to be 20 cups of coffee a day and now i average at 2 ...5 or 6 if im having a bad day...and energy drinks, i try and only have 1 redeye a day...but ive been known to have 4...(max on bottle is 2)
in saying that i can still have that and not have a problem sleeping at night at all...i do wake up often but ive always done that way before i started on the caffine (when i was like 15..)