If you're in the design field, I think it's safe to assume that you're probably a creative-minded person. Like many creatives you probably have multiple outlets, and you don't like to be limited. If you're trying to make a living in design though, it's natural to start feeling like maybe you should really focus on design at the expense of other forms of expression. To an extent, yes you should remain focused, but it's also important to take breaks and explore other forms of creative output.
Sean McCabe takes one week off every 7 weeks to pursue his music as well as other creative outlets. If you're like me, you're probably not in a place where you can afford to do that, but his argument for the small scale sabbatical is a compelling one nonetheless. I personally feel it's important to take a day to shut off the computer and put that creative energy into something else.
The other day I was feeling a bit burnt out. I was up late the night before doing some website jiggery-pokery, and got up the next morning feeling drained. I didn't have any client responsibilities so I decided to take the afternoon to get away from the desk and do something hands on.
I have a couple creative outlets, including music and writing. But I also have a love of Lego, which is what I ended up pursuing for several hours. I put on some music and set up a workspace on the floor in the middle of my apartment. I always have a goal when I start a project, I'm not usually one to aimlessly create, this time around it was to create something sci-fi. With an end product in mind I got to work. When I was finally finished I felt that I had accomplished something, which got me in the right frame of mind to get back to work.
It's extremely advantageous to take whatever time you can to find other creative outlets outside the one you're building your career around. Whatever time you can dedicate, wether it's a few hours or a few days, use it. Find something to do outside of design. Put away the computer and create something tangible.