In the year or so that I've had my D4 I've taken my camera into the shop 4 times to get the sensor cleaned. I find that when I swab it myself I make a mess of it. I don't know what I'm doing wrong but I always end up moving the dust around.
I'd love to hear how often you all clean (swab) your sensor or bring it in for cleaning. The dust drives me nuts but I'm not willing to let that stop me from changing a lens out in the field.