I had a somewhat similar trajectory to the author with coffee. I started drinking it in highschool and loved it. I didn't have quite as bad a sleep schedule as him, but it was bad, and coffee was the band-aid. Then I got to college and really went nuts. I used to just get coffee in the morning, then it was before every class, then after class too, and in the evening when I was doing homework. Every coffee shop had free refills, it was so cheap. Eventually I got to the point where I was drinking 10-15 cups a day, and I was starting to have a lot of trouble sleeping, presumably due to drinking it late into the evening.

Then one day I just decided to stop, and it was shockingly easy. I didn't have any withdrawal symptoms, not even a headache, I didn't feel particularly tired. And I started sleeping better so I quickly felt less tired. I think my dependence on coffee was entirely psychological, there wasn't really a physical component to it.

I haven't really had coffee, or any caffeine since then. I went through a period of drinking decaf, but found that even the little bit of caffeine in that messed with my sleep. Or it was just a placebo affect that made me too anxious to fall asleep, still not really sure which it was. The only thing I really miss is the taste, every time I walk by a coffee shop and smell it I get a wave of nostalgia. But oh well, I like sleep a lot better than coffee.