Caffeine helps me focus in the short term, but if I drink it too late, it might keep me awake longer than usual. If I need a quick energy or focus boost, I'll drink an energy drink. Also, something my gf and I enjoy occasionally is a latte (this is pretty much just espresso and milk, but still has come caffeine). Overall, I'd say caffeine helps me more than hurts me as long as I don't drink it too often or too late!
Prancer