I've heard about the Canon 1DX throwing oil onto the sensor from the shutter mechanism. I never owned one so didn't quite appreciate the issue, but my 1DX Mk II makes quite a mess if you look at the sensor at the level of detail I do.
I'm wondering if this is something that tapers off with use?
I suppose it's not a bad price to pay for 14 fps and a long shutter life -- something has to lubricate the moving parts. The oil spots are tiny and wouldn't show unless you really know how to see the state of the sensor, but after a few days of shooting something like 500-800 images a day, many in bursts, I wouldn't like to think about letting them accumulate for long.
I show a good way to see the state of the sensor and to clean the oil in a tutorial on my web site.
Thanks for sharing your experience and for the tutorial.
After about 2000 shots I tested my 1DXII and noticed few spots at f/32 (with macro 100 L lens). At around f/13 the spots were not visible. Looks like oil spots, not like dust. I did manual sensor cleaning and after >10000 shots no issues any more. On my 5DIII I did manual sensor cleaning around 1-2 times per year. Hope 1DXII will be in the limit.
I had another issue. When I got my 1DXII I noticed a small hot pixel at the bottom of each frame. I found somewhere on web the solution (not clear which EOS models are covered with this option). Run Setup - Sensor cleaning procedure without attached lens but with the regular cap placed on the body. In this case during sensor cleaning procedure the software removes any hot pixel and stores the new configuration. It was working on my 1DXII.
However I'm happy user of 1DXII. Big forward step for me.