I've been on/off caffeine numerous times. Mostly because I have a big backpack trip where obtaining caffeine is a pain. It takes exactly a week for me with days 3-6 being miserable. I feel I am not fully "there" almost as if I'm an observer in my own body.
There are two advantages I see in being off caffeine. First you are not dependent on a drug. Second, if you do need the drug for a rare occasion (maybe driving late into the night etc.) it is there for you. Being off caffeine then drinking a cup of coffee gives you a huge jolt.
I got back on caffeine recently to see if it would help me lose weight. It did not. Now I'm fat and addicted.