One of the most important things I learned from watching my parents during my youth was that neither considered a day spent reading a great book wasted time.
One of my previous employers had this mentality, although I think I was the only one to take advantage. Spending three weeks researching the history of a site (on company time) was NOT wasted hours. As a result, I learned more about the San Antonio missions than any human probably should – and it changed me and the way I approached our designs for the project.
Now that I’m in business for myself, and reading and learning are more critical than ever, why does it feel like reading, writing, or anything not billable, is “unproductive”? Perhaps because you can’t put a dollar-value on it. In design services, you aren’t supposed to say “I know much more this year than I did last year, therefore I am more valuable and my billing rate is going up”, although it should.
If for no other reason than stress relief, make reading (and being 100% mentally present) part of your routine. You’ll find it makes the rest of your day much more “productive”.