I used to be a caffeine junkie. Weirdly, however, after hitting a rough patch this year and deciding that I couldn't afford 4 2L bottles a day any more, I found that I was no less productive without it, and I'm far less anxious. I have an occasional caffeinated soft drink or green tea, still, but the non-stop highly-caffeinated Randall days are no more.
there are caffeine pills that are cheep as dirt.
Also, it only took me about 3 days to feel normal, and a coupla weeks to not really want it very much, after 5 years of averaging between 3 and 4 2L Diet Mountain Dew a day. It helped that my wife was very vocal about how much less stressed I seemed; after I was off of it, she suggested I just stay off even when I can afford it, so I'm doing that for now.