First: I know, it's the "low pass filter," not the sensor that gets cleaned. But I used that heading since that's the standard "term of art."
I was hoping to avoid the problem by changing lenses rarely and carefully, but finally I had a speck of dust on my sensor. Some questions:
1. How to check. What's your procedure? Is there any way to check thoroughly without a large monitor?
2. How to clean. I've been reading on the Internet, but I'd like your working pro's opinion. Is it even advisable to try this in the field, or do you do this only when in a clean, controlled setting?
3. When to check. When is the sensor actually vulnerable to gaining a speck? Is it only when you change lenses, or is it more random? In my film days, we "checked the gate" regularly. I even bought an otoscope to make sure I could see the tiny hairs that turned into giant, flapping dragons on the screen.
4. I use a Canon 60D, which has an automatic sensor-shake on power-on. Would you advise cycling the power-on a couple times, just to increase the chances that the self-cleaning gets rid of any specks?
5. Does my "change the lens rarely" system actually help in any significant way? Camera bodies are pretty inexpensive; I wonder whether I should add one.