I gave up coffee some months back. I was only having a large cup in the morning bullet-proof style, but I noticed that I was having trouble falling asleep so I tried an experiment. I switched to buttered tea, and now falling asleep is easier. I've always been pretty sensitive to caffeine, but I also think that coffee was stressing my adrenals which was causing the difficulty with sleeping. While I loved the taste of coffee, it's not worth having it mess with one's sleep.