Chores like this are a good time for multitasking. You can sit and stare out the window and think, or you can walk to the store and buy office supplies and think. In the second case, you've done two things at once; spent some time thinking, and got your office supplies.

My apartment is very clean because I like to do something while I am thinking. Cleaning involves no thought on its own, and it's nice to not see any messes. For me anyway.