I too quit caffeine for 9 months in order to try and fix a perceived 'energy and alertness' problem. I was pretty serious about the affair and had some help from my wife to not only avoid coffee and tea but also the myriad snack-foods that sneak the stuff in. I've never been a soda drinker and consume nicotine about once per month.

The effects were negligible, the effort was an unproductive deviation from my normal routine and I stopped before a year had passed.

I did eventually fix the perceived energy problem. The answer (in my case) appears to be that I was spending too much time asleep in each 24 hour period.