Cleaning a sensor (wet or dry) is something that all DSLR users should learn. It's a basic thing that is not so different from negative cleaning when we were in the dark darkroom age. I don't see it as a problem unless the spots won't go away with a good wet cleaning. I did notice some dust on my D600 last weekend when I did a few HDRs. By the way, HDR is a sure way to tell if you do have some dust on the sensor since it exagerates these to excess. It only took me about 10-15 minutes to clean, check, clean again, check and then I was fine. It takes me less time to clean my sensor than it takes me to clean my car… So, why should I complain.