Vladimir Starkov suggests to read at least two technical books a month.
It’s very important to be up-to-date with latest trends, especially in so fast changing industry as frontend development. But there are so many interesting subjects besides programming languages and new frameworks.
I love to read about design, typography, photography (more about philosophy than technique), languages, writing, people and other subjects.
Reading for me isn’t merely source of a new information but by and large it’s a pleasure of a good language. People who write about tech stuff usually aren’t the best writers and their books often are just boring.
Unfortunately I don’t always follow my very own advice: most of the books I read are tech books. And I read fiction not as often as I should.
P. S. And of course don’t forget to go outside with a good non-tech book.