I'm on my second D600, the first returned because of dust I could not remove. (Blower) I used the second camera for about 500 shots without a lens change making dust reference shots as I went along. I then employed very careful lens change habits...clean the exterior of the camera, new lens etc...before changing.
The dust reference shot at about 1000 exposures was very dirty, but a careful blower cleaning removed all but four particles...grease? Zen and the Art of Digital Sensor Maintenance should be required reading for all D600 owners.
I've not seen, but may have missed, the suggestion to use dust reference shots in post process and "heal" those you can see. Then "sync" their removal for all the shots in that folder. Then remember the Zen advice...it's not that big a deal.