We had our kitchen painted last November and I had to take down the decorations I had above my cabinets. In all honesty, they were not that dirty. It was a few ceramic pots and a few baskets. Now, mind you, we are not cooking up a greasy/steamy storm everyday. After the painting, I put even more things up there and it looks nice.
Now my MIL, may she rest in peace, is another story. When we cleared out her house, the stuff above the cabinets was disgusting. You could not tell by looking up there beforehand, but holding the items was disgusting - dust sticking to grease.
As far as cleaning up there every week, surely you jest, LOL!
Always remember that you are absolutely unique. Just like everyone else. Margaret Mead