I live in Utah. Think lots of dry desert. The dry air creates static. Nearly every time I take off a lens I get dust. I use a rocket blower for what I can, but it accumulates after a few months. I have tried swabbing it myself but I seem to just make more of a mess. The dust ends up along the edges and I'm always unhappy with the result.
Hence, I take my cameras (a D300s and a D4) to my local shop about twice a year for a cleaning. $35 and a cup of coffee later good as new. Very much worth it in my book.
I have heard great things about the Arctic Butterfly cleaning tools. They're expensive but perhaps worth it if you don't have a good local shop. For me, I'll stick with the twice yearly cleaning done in-shop.