Okay, I don't work smaller than f5.6 most of the time, and more often around f2 and so I appreciate I'm less likely to pick up on visible particles of whatever on the monitor. The reality is that in at least eleven years I have never cleaned a sensor. I never change lenses outside, so that obviously helps, but that's not my point.
I was really going to say that there is a parallel here with film camera screens too. Until I removed the pentaprism on my first Nikon (F) for the first time in order to put on a grid screen instead of the standard split-image, that prism showed spotless images. After that, forget it. I saw dust, minescule hairs, all the rubbish of the day on the only two screens I ever swapped around. It became impossible to get rid of static, and hence the magnet-like attraction for passing devils. My wife even brought me a supposedly non-static brush from the lab where she worked but it made no difference, so I ended up using a tiny paint brush again. Only reward I ever got from my box of Winsor & Newton water colours. :-)
I think that any touching created havoc. Of course it's different because the sensor dirt is equivalent to dirt on the film, and thus can't be ignored, but could it be that sensors are even more prone to static electricity charges?
Perhaps that, aside from exposure metering challenges, could be a reason digital cameras don't allow prisms to come of - insofar as I know.
