Sun 04-Nov-12 01:59 PM | edited Sun 04-Nov-12 02:00 PM by RLDubbya
I've had my d7000 bodies for 10 months. One body has 9500 shutter activations, the other, 4500. I haven't cleaned the sensors yet.
I try to keep a 24-70 zoom mounted on one body, and a 70-200 mounted on the other body when I'm doing only still work. Sometimes, I'll have to toss on my old kit lens which is wider, especially if I'm shooting video.
I do what I can to minimize lens changes. When I do change lenses, I make sure to do it quickly, including capping the rear element of the lens coming off.
I don't bother with a rocket blower, although I have one. Thom Hogan (bythom.com) has a nice article on sensor cleaning, and one of his observations is that use of the built in vibrate function is as good as a rocket blower for knocking dust off the sensor. I have that set to vibrate at both power off/on, and try to remember to keep the camera held horizontally as though taking a photo, so that the dust falls off properly.
I do keep canned air back in my office / studio. I use the canned air to blow off the front and rear of the lens prior / post shoot, and obviously if I see any dust, etc.
I try to keep my office / studio clean, so that there's not a lot of dust floating around where I clean the lenses. I don't know if that helps much, but...I also use an air purifier in that space, which does help to minimize dust.
I'm pretty sure (just based on a gut feeling) that if I took a picture of the sky at f22, there would be a lot of dust particles show up. I don't normally take pictures of the sky at f22, so I don't really worry about that. I'm lucky if I get to use f5.6, honestly, most of my shooting takes place indoors or in heavily shaded areas.
EDIT: I had a D5000 prior to my D7000. I had it for about 14 months, ran up 18,000 shutter activations, and never cleaned the sensor.