One way I've heard personal/professional development described is as follows: "You have two jobs (three if you have a family). You put in ~40 hours/week for you

One way I've heard personal/professional development described is as follows: "You have two jobs (three if you have a family). You put in ~40 hours/week for your employer, and ~20 hours/week for yourself. In those 20 hours, you work on yourself (both physically and mentally). Exercise, read books, learn new things, develop new skills, improve yourself. Ten hours per day is probably not realistic if you work full time (unless you can overlap your time somehow). An hour before and after work, along with some free time on the weekends should be enough to get started.