I gave up coffee once, for a few weeks in the summer between college and grad school. I had been drinking 3-6 cups a day, and one day I just stopped.
I spent the next three days addicted to Tylenol and mostly lying in bed, miserable. But on the fourth day I got up and was fine. In fact, I was pleasantly surprised to find that my mood and energy level stayed about the same all day…I had assumed that the typical day was full of peaks and valleys, but it turned out that was just the caffeine talking. Without caffeine, I felt remarkably steady and consistent.
The drawback turned out to be that without caffeine, I needed no less than eight hours of sleep per night. I would get sixteen good hours awake, but then crash entirely. Once I started grad school, my workload didn’t permit a full eight hours sleep per night…or so I saw it at the time, anyway (this was about 15 years ago). So, back on coffee I went.
Nowadays my normal intake is 4 cups a day: 1 after each meal and maybe another one mid-morning. Lately, though, I’ve redistributed the dose: I have a cup in the morning, then take a thermos to work. Through the working day, about every 60 to 90 minutes, I pour 2-3 ounces in my cup and drink it. The result is the closest I can get to the uncaffeinated steadiness I briefly knew. I still have a cup after dinner, though.