How familiar are you with measuring tools? It is amazing that we have different measuring tools that have been made and used through the years. They make life a bit simpler for us. We do not have to rely on our inaccurate estimates. When we need to make measurements, we can use the appropriate measuring tool or device and we can have the data we need.
I admit my limitation in knowing the measurement tools that are now available. They can talk about height gage and the like and maybe for a moment, I would not be able to picture in my mind how it really looks like. But the more important thing is it is there somewhere and when I need to use it, it can be found. :)