Warren in Lancaster, PA
The problem with the experiment is that a plane does not suddenly get dull, it dulls gradually over time. When I have had beginners working in my shop, they have to be told when it is time to sharpen because they can't notice the gradual deterioration of the edge.

It is like buying a loaf of bread on Monday and making a sandwich every day. By Friday the bread is a little stale, but you don't notice it because it is not that different from Thursday's sandwich. When you buy another loaf the next Monday you do notice that it is fresh because of the contrast to the week old loaf.

A better experiment is to sharpen after every other drawer and see of you can notice the fresh sharpening.