I've never really suffered from any of these problems. Every day I set myself up for 7.5 hours of work, and 2 hours of breaks/checking email in the morning/lunc

I've never really suffered from any of these problems. Every day I set myself up for 7.5 hours of work, and 2 hours of breaks/checking email in the morning/lunch. After those 9.5 hours are up, I'm free to do what I want. At a bare minimum I do 37.5 hours a week.