After being somewhat of a lush from my senior year of high school to about 23 years of age, partying a little too hearty, I stopped drinking because I just didn't see the point of waking up with a hang-over and wondering where the $50-$100 I had the night before went. The novelty wore of, I suppose.
Then I went through a dry spell for at least three years, didn't have a drop, not even during the holidays. Then a couple years where I would have a drink at New Years or something, but usually didn't finish it.
Now I'll buy a bottle of wine or six-pack of beer and it will last about a month.