I've been adopting this approach in order to have higher-quality free time. I find that if I wake up early (around 7:30) then I can take an hour or so to myself in the mornings to read, play a game, or work on a personal project, and I have my full brainpower to apply to it. However by the time I get home from work around 6, I don't have nearly as much energy to put in to the same activities, and can't focus as easily or make as much progress.