I leave my office delibately cluttered and intermingle my personal belongings with those that belong to my employer. A couple times, someone has had the bright idea to clean the store-room that is my office and both times they wound up throwing away something important.
I get bitched at for having a messy office (no one can find my phone, for example) but since I'm in a windowless room with no ventilation, on the far side of the building from everyone else and I have to keep track of all the cables, power supplies, spare parts and software that people need, I don't feel any particular obligation to waste my time on being tidy.