I also want to mention that I shot for a few years in probably the harshest conditions of most anyone on here...rain, dust, rocks, light etc. all exposed to elements and bouncing across the rocks in a crawler for 12 hours or more a day with nothing to do cleanings with.

Sensor dust happens and is easy to PS out of the shot, clean lens rag is your friend...in fact I carry a dozen or so every time I leave with my camera, lens changes are quick and easy, like Vinnie said about 3 seconds if you plan it right and this minimizes and nearly eliminates any dust issues.

I have cleaned my sensor every time I come home from a shoot because the conditions are just that bad when I shoot, but it is far from debilitating in any way.