I got off the caffeine wagon (black tea) a few months ago now. I don't know if getting off improved my sleep since I take Clonazepam & that pretty-much knocks me out at night regardless. But I was surprised at how much of the energy I had during the day, while I was still drinking black tea, was fueled by the caffeine in it. Sometimes I think I should take up the practice again to see if it would perk me back up. But now that I'm off, I really prefer to stay off. So my plan is to stick with Camomile when I want a hot beverage... which I'm sure I will come late autumn & winter.