Twice now, I have deliberately gone cold turkey on caffeine for a month. Both time, the results were the same; while I didn't completely lose my programming ability by any means, I totally lost my best programming times, and in general felt slower and fuzzier even during the rest of the day. From what I can see, after a month off of it I should be adjusted to its absence.
Since then my situation has been changing some, and once it stabilizes I plan on trying again (learning I have celiac disease, changing some other elements of my diet). So this may not be generally applicable. But I will say that if you are nervous about your caffeine consumption, try dropping it for a month and seeing how it goes; it's not that hard.
Twice now, I have deliberately gone cold turkey on caffeine for a few weeks. Both times, the results were the same: 3 days lost to caffeine withdrawal headaches, followed by no noticeable differences in anything.
Also, when I got back on caffeine, I noticed nothing. And I should've been my most caffeine sensitive then. If I did a seriously huge dosage, I'd have shaky hands, but otherwise nothing. I wasn't more alert or awake or hyper or anything.
Caffeine does supposedly have Ritalin-like effects on ADHD kids, so maybe I'm ADD and don't know it.
Since then my situation has been changing some, and once it stabilizes I plan on trying again (learning I have celiac disease, changing some other elements of my diet). So this may not be generally applicable. But I will say that if you are nervous about your caffeine consumption, try dropping it for a month and seeing how it goes; it's not that hard.