I used to have 7 Nikon D600 and 3 D610. All of the them were returned except one due to the dirty sensor. Even the last D610 has been sent back to Nikon for warranty service twice. This review is for my other camera, D7000, having the same problem though. It is over a year old and has only 950 shutter count. It accumulated 20+ visible dirty spots without too many of lens changes. I don't want to clean the sensor myself because it is a critical job. I've done it before without too much of fun. After reviewing camera repair shop in town, I decided to go to this shop because it is more reasonable in price and it is done by an experience professional, not by a technician hired by a company. It is not a short distance from my place. I ask the shop owner, Morris, if I can wait for the repair. He said OK for an hour. After having the lunch, I was told it took him 6 passes to get all the dirt out. Luckily, I didn't do it myself. Coming back, I compare with the jobs done in Nikon Service Center. It appears the cleaning quality is better with Morris. That confirms my theory that a junior technician doesn't come close to an experience professional.