Caffeine dependence can lead you down a shaky path... pardon the pun.
First thing in the morning your body naturally produces cortisol to help you wake up, and harsh sources of caffeine like coffee spike cortisol - which also happens to be the stress hormone.
Delaying these sources of caffeine a few hours into the day allows your body to wake up with the natural mechanisms it has in place, without disrupting the production of the necessary hormones.
It also, from my experience, provides much more bang for your buck, and doesn't leave you craving more throughout the day.
A coffee once I wake up often leads to a coffee mid-morning, which leads to a coffee after lunch, which leads to a coffee before my workout - which is more coffee than I know I'd like to be consuming.
Switching to green tea first thing has worked wonders for me, providing a more stable boost in performance - without the spike in cortisol. Saving coffee for later in the day.
At night my rule is simple, no caffeine after 4 pm, unless before a workout.
Coffee improves training performance in a number of areas, and through my experience sleep isn't affected by this later consumption if followed by a workout.
As always, we are biologically individual and thus tolerate caffeine differently, so it's important to know your tolerance and act accordingly.