Dave may be correct, and conditions in wetter, more humid environments may affect the magneto.
I lived in Western Nebraska. We had two Model D Jon Deere tractors, two combines, two MM tractors, two IH tractors, one AC tractor and other engines with magnetos. We never had one Magnito failure and never adjusted or even checked the points.
Im not criticizing Dan, just relating my/our western Nebraska experience. However every machine that had distributors had match books in the tool box, the cover was the proper width for setting points. I’m 80 years old I knew how to set points when I was 14 years old when I started putting in long days and weeks of tractor driving. It was a fun life to be able to play with real toys, plows, cultivators, grain drills, corn listers, sickle bar hay mowers, side delivery and dump rakes, balers, skip loaders.
At age 12 I knew how and when to pull a calf, how to push it back into the womb, out my hand into the cow to turn the calf around so the front feet and nose come out first, knew where to drive a sharp knife into the first stomach of a bovine to release bloat, how to casterate, dehorn, and give shots to animals, etc., make butter, slaughter chickens, etc. life was quite different then. To this day I dislike urban living, crowds, cities, and vehicles in which I can’t hear the engine run. And new paint.
sorry for the history lesson, but that’s who I am and I guess the way I am. Different strokes for different folks.