My drafting/lettering teacher was very particular. He would underline an ok letter with a red line, a good one with two, and an excellent one with three.
Lettering wasn't all of it in that class, but it was what we spent most time on. Back then, speed lettering was a key tool.
Some time later he was and still is a pal of mine. His natural writing is sort of miserable, to be truthful. He had learned precision and taught it.
Adds, he has for years identified the flora in a lot of wilderness and drawn what he saw. All that lettering helped his hand eye connection.