I've had the same header for almost a year, the same layout since January 2011 and the same sidebar buttons since I started my blog over two years ago. And this weekend, I finally changed it! It's not a huge difference ... I doubt anyone will be like "wait, what blog IS THIS?!" (In fact it's quite possible a lot of people won't even notice I did anything) but I really love the little changes I made!
If you're in a reader you can click through here to view the new design! :)