I drink 2-3 cups of coffee a day (or double espressos) and have done so for about 20 years. Usually the first thing I do when I wake up is drink coffee. When we had our first child over three years ago, my wife said she wanted me to stop drinking coffee for a few months so I could nap on demand. I quit cold turkey. It was fine. Several months later I went back to drinking coffee and it was still fine. There was definitely a noticeable difference but nothing like you're talking about.
Everyone's sensitivity to caffeine is different. For example, if I miss my one 8 oz. cup each morning, I have a massive headache by 1:15pm.
When work picks up, like a big project, I might increase my intake to a larger 12oz or 16 oz coffee per day, but then I'll end up sustaining that too long after the project ends.
After a while, I'll do a cold turkey reset to zero caffeine. It takes 4 days and about 800mg of Ibuprofen each day to make it through the headaches. Luckily no other withdrawal symptoms.
I have friends that only drink coffee on weekdays... I don't get how that can be done! For me, coffee is preventative medicine.
As you said, everyone is different. I drink coffee (~2 shots of espresso) almost at the exact same time every morning. Then again after lunch.
There's basically zero impact if I miss the morning one.
I've done multiple stretches of not drinking coffee (weeks/months), with also basically no noticeable changes: not more or less tired, no change in sleep, etc.
Huh. Your comment made me realize something weird: if I drink coffee in the afternoon or evening I have a hard time falling asleep at night... but I can almost always do a little daytime nap, say at noon when I've drank my customary two cups of morning coffee
I've quit a couple times and always get those symptoms. At the very least id get massive headaches. Also if you're drinking that much is it very weak coffee? I'd use a mocha pot
I try to keep it to once or twice a week at most, and around lunch time, as I still like coffee. But this way you don't build a dependence.
This year I quit cold turkey and holy crap, night sweats, panic attacks, flu like symptoms for several days.