This is a sound advice. I spent 10 years of my life trying to squeeze as much time awake time as I can using tons of coffee and that almost ruined my life and got me nowhere. I have managed to get some success in life once I gave up on that idea and was productive when I was feeling productive without forcing it. If I can't do anything during the day? Fine. If I feel sleepy? I go to sleep. It was important though, to wake up at the same time in the morning. I was unable to kick off the coffee addiction, but reduced it just one cup in the morning. I find coffee more difficult to quit than cigarettes.