I've gone off caffeine a couple of times, each for a period of about 1 year. If going "cold turkey" (which I did and don't necessarily recommend), I found it took about 2 weeks to return to baseline without headaches or other withdrawal symptoms. After this point it's mostly smooth sailing: I no longer felt I needed caffeine to wake up in the morning and didn't have any cravings.
On average, my sleep quality was quite a bit better. It was usually easier to fall asleep at night and wake up feeling rested. Overuse of caffeine can make it hard to feel tired at the end of the day, which can cause a vicious cycle of insufficient sleep leading to more caffeine use, etc.
On the flip side, during my periods of abstinence I found I would eventually start to miss it. A good caffeine buzz is one of my favorite small pleasures in life; I've had many of my best and most creative productive periods assisted by it. In addition, I also just really love the taste of good coffee and the ritual of preparing it in the morning. While the latter can be satisfied by substituting decaf, personally for me there just isn't any replacement for that feeling of being "in the zone" on caffeine where it feels like all my neurons are firing and forming connections rapidly, and the ideas and creative output just flow effortlessly.
As an aside, I do suffer from minor persistent depression, which is possibly one reason why I find caffeine helps to give me an extra boost to feel like a normal functioning person :)
To date I've found that totally abstaining from caffeine isn't the best fit for me, but I've learned over time to use it more moderately. Some of the measures I currently take that seem to keep me in a healthy balance:
- Maximum of 2 cups of coffee per day
- Practice being more mindful of caffeine consumption: I have one cup every morning around 8am, but instead of mindlessly chugging it throughout the day I will check in with myself before having another. If around 10-11am I feel like I really need a second cup, I have it. If I don't, I drink green tea or seltzer water instead.
- No coffee after ~2pm. If I feel groggy or tired after 2pm I'll try drinking a low-caffeine or decaf tea instead, or going for a walk. 9/10 times just the act of drinking something hot will be enough to perk me up. This is probably the most helpful change I've made, as avoiding caffeine later in the day ensures I can sleep properly at night