One of those oddball things that came to mind when considering bike maintenance:
Grew up in a small town for a number of years, late 60's-early 70's. Everybody who could talk their parents into it and get enough together got their motorcycle license when they turned 14(guys; never saw a girl get one). Most were Honda or Yamaha single-cylinder, 75-100cc(at that time in OK if you were under 16 you couldn't have a bike over 100cc for road use).
It was wheat country, which means, especially spring/summer, lots of dust in the air. One guy had a Honda 90 that started burning oil badly, and had the engine rebuilt: bored-oversize cylinder, piston and rings to match, cleaned up the valves. Ran beautifully.
For about three months.
At which time it was smoking like he had a wood-burning steam engine in the thing and you could smell the oil. He started griping about what pieces of crap Honda made, and one day I asked when was the last time he'd cleaned the air filter(remember, back then it was a foam filter you soaked some oil into):
"I took it off."
I don't really understand why, but I'd gotten something of a reputation of a bike guy; apparently reading the owner's manual for things like the filter and adjusting clutch and brake cables was good enough. So I said "Why?"
"Because you get more power that way!" Accompanied by a look of 'you didn't know that?'.
"Well, that's why it's burning oil again! Without the filter it's sucking in all this dust and it's grinding the rings down!"
This was a guy who had family who farmed, not exactly unacquainted with mechanical stuff, but for some reason the fact of what that filter was there for hadn't really sunk in. Or what would happen if you didn't use it. The look on his face, I'd have to describe as 'Dawning Aw Shit'.
Amazing what comes up out of the memory hole