I quit coffee in October and drank only yerba mate and tea until my injury when I quit all stimulants basically because I was in too much pain to want to be alert and I was resisting medication. After surgery I had to take narcotics for a week, and after that I felt like I couldn't read. After seven weeks with no caffeine I decided to measure my mate to insure I was being moderate. I felt too buzzed after a fraction of what I used to drink!
Caffeine in moderation is not unhealthy. If you're thinking about learning to moderate I suggest going cold turkey for at least a couple of weeks and then easing back into it. Once you do, make rules and stick with them.
I wouldn't suggest this for alcohol, btw...