I'm sick. I run everywhere with a bagful of primes, and I switch lenses all the freaking time. I really need to learn to leave stuff behind when I go out and shoot. I don't have a body that shakes the sensor clean, but I do live somewhere very dry, so a Rocketblower tends to take care of my sensor dust problems for me. I puff off the sensor when I pack up to go out for a shoot. I also know how to clone out dust spots in Photoshop.
I typically minimize any problems during a lens switch by using the body cap. Remove lens, put the body cap on, and then take my time to stow the "old" lens, and prep the new one. When it's ready to go, take the body cap off the body, and good to go. So the body is "exposed" for only a second or so each time I'm changing lenses.