Unless your lens is weather sealed, not changing lens will still attract dusts. My friend never changed the lens on his 5D, but dusts still gets onto the sensor.
Just always have a blower ready and blow the dusts away as u see them. Get rid of the dusts in photoshop if they appear in pictures.
If people want to make such a big deal out of it, do this:
1) build a vacuum box with gloves attatched to the box.
2) put your sexy lens/camera in the box and seal it.
3) turn on the vacuum and suck out all the dusts.
4) close the vacuum vents immediately after 2 mins.
5) do everything in the vacuum box with the gloves.