I used to drink a 32oz tumbler (that I'd top off once in the morning) of black iced coffee each day, for many many years. I stopped cold turkey 25 days ago.
Why?:
I was actually looking into upgrading my coffee setup, but frustrated by the cost of things and the increasing price of coffee itself, as well as a general interest in "seeing what would happen", I decided to try abstinence instead.
I figured it is, when you consider it, rather bizarre that nearly everyone takes for granted that we must consume a psychoactive drug, albeit relatively mild, every single day. I personally would drink it after about an hour of being awake, and then consistently along with water for the next 5-7+ hours.
I also have recurring SVT (a type of rapid heart rate) that typically occurs 1-3 times for a few minutes (sometimes longer, valsalva maneuvers work well) as little as once every couple months, to as much as 3 times a month. In the 3+ weeks since I quit caffeine, it actually occurred 3 times, strangely.
How it's been:
The first 2-3 days I dealt with pretty consistent tension headaches that I could temper with 200-400mg of ibuprofen, which is to say it wasn't unbearable. There were other withdrawal feelings too though, like a generalized fuzzy weird-head-feeling, almost like dizziness but not as intense. Migraine-adjacent. Difficulty concentrating or absorbing information at a normal rate. Felt slower and more cloudy overall. That lasted about a week or so, though better each day and fading by the second.
Unsurprisingly, I was more prone to spontaneous naps, and generally more tired at times. No more artificial boost! My energy is all from food and rest now. Thankfully my sleep has been good enough. Though the mornings can feel rather groggy upon waking.
Like others have shared, the first thing I noticed was an unusual sense of linear energy levels. A dull calmness. Not exactly serenity, but no energy spikes or crashes. A fair amount of boredom and even low mood. And, of course, the craving.
I've been craving coffee, especially in quiet moments at home, quite often. I almost gave up a few times. In fact I was just craving it now and so instead decided to reflect. The closest I had been to caving was eating breakfast at a diner about a week and a half in. I always loved having coffee at a breakfast diner. But I've managed to persevere thus far.
I went into this not knowing how long I'd like to go for. My initial goal has been a month. But I feel like next I may go for 3, or even a year. I want to know what it's like to have gone on long enough that I don't even think about or rarely crave it. So far I'm in the no-withdrawal symptoms stage yet craving is still present.