In addition to the time factor, focus can get harder as you age https://www.health.harvard.edu/mind-and-mood/how-memory-and-.... Early am seems to be the best time for optimal concentration/focus, so your suggestion is a good one. It also heads off decision fatigue, which makes it harder to focus later in the day: https://www.nytimes.com/2011/08/21/magazine/do-you-suffer-fr...