Hmm, I quite caffeine for a bit more than a year. I didn't feel like I had more energy per se, but I definitely felt better overall. It did take a long time to get through withdrawal.

This overlapped a period of two springs where I had terrible, terrible allergies, which claritin/etc barely helped with. As a test I drank coffee for one week, and the allergies completely vanished. :(

I've firmly stuck with 1 cup a day, though, drinking decaf after that. I think only drinking coffee right after I wake up probably helps.