Ask HN: How do you balance your life as a knowledge-based worker?

Or more specifically, how do you balane your life as a knowledge based worker when there's so much to learn and so little time to do it all?

I am a physicist who specialised in molecular simulation. To be excellent at my work, I need to have a strong understanding of theory and compututation. For theory, I need to master classical mechanics, statistical physics and have a strong general grasp on advanced mathematics. Computation entails having a good understanding of my tools (unix, various programming languages) and the computational techniques that are used in my field (parallel computing and various algorithms). I've been hammering away at learning these over the last two years in addition to my academic work. I love it! I'm passionate about it and the more I learn the more capable I get.

I don't, however, have much time to do anything else. I enjoy music and art, but I can barely fit things in enough as it is. Even worse, the more I learn the more I realise that there's so much more to learn. I can easily say that I'll pursue my passion for music at a later date, but at this rate I'll only have time for guitar when I'm in my eighties! I'm currently stuck in a cycle where I suddenly have an urge to study, say, jazz guitar. I then pursue it for a week or two before realising that the time I spend studying jazz could be spent studying physics, and that I'm not as good as physics as I want to be. I stop and spend a month or two on just physics... and then I get an urge to study pen and ink drawing.

I see a lot of other users engage in some genuinely awesome hobbies whilst simultaneously being experts in one or more technical fields. Some of you are insanely good at your hobbies, too. How exactly do you manage to develop and maintain your technical skills whilst pursuing something completely unrelated? How do you fit it into your schedule?