My max was 48 hours/week ( but this is an exception )

For living I build e-commerce solutions and backend stuff. And in free time I play more with a frontend. Recently with react/redux and in the long run with every possible new technology on the horizon. I guess I waste a lot of time doing this as most of these things isn't immediately related to client work. ( but over time It helps me to sell to them a few ideas for improvements )

Also, I track my time and habits in detail ( using rescuetime ). Probably without such careful loging I would overestimate how much time I am spending on actual coding.