In Sanding UI, Jim Nielsen writes about the practice of making changes to UI, then using it over and over again, kind of like feeling the surface of sanded wood to see if there are splinters.
But I like to think of it as being more akin to woodworking. You have a plank of wood and you run it through the belt sander to get all the big, coarse stuff smoothed down. Then you pull out the hand sander, sand a spot, run your hand over it, feel for splinters, sand it some more, over and over until you’re satisfied with the result.