I think I still have a few “worn-out” Cessna ignition switches in my old toolbox. I am not sure if it was a manufacturer thing or if our many new students had anything to do with it, but we changed them very frequently. Of course you do turn them a lot more than a car ignition switch when you hopefully do your magneto checks. Also, it is 1970’s or earlier technology. We had a few keys break off as well. That one I was chalking up to either getting in and out of the aircraft funny, hitting it with your knee, or just being so tense on run-up that they muscled the key right off.
Of course ANY weakness in any aircraft immediately falls prey to Chuck’s lucky hand with technology and short attention span. In the Chinook we have a parking brake handle that immediately let’s go and slams into a very hard to replace micro-switch for the advisory light if you don’t hold on to it while you push the brake pedals. Obviously a weak point in the wrong hands. And in true Chuck fashion it didn’t take me a long time at my new job before that handle slipped out of my hand (it’s hard to reach from the left seat) for the first time. You should have seen the mechanic’s face! It looked just like Stefan draws Julio’s face when Chuck messed up. The switch was fine in that case (I was lucky) but beers were owed nonetheless.