Maybe jimmyd13 can tell us if there is a date on that publication, but my guess is that is was before the advent of white alloy mainsprings. Back when blued steel springs were used, mainsprings breaking was a very regular occurrence as they were brittle. But the new "unbreakable" mainsprings have really made a huge difference with how long these mainsprings last:
Of course they aren't really unbreakable, but compared to the older springs it probably felt that way.
Also noted the advice to get the watch "cleaned" once a year, and they go on the talk about a proper service including full disassembly of the watch, clean, lube, adjusting. The use of natural oils back then meant that when the oil aged it would gum up and stop the watch, and it didn't take long for the oils to fail compared to modern watch oils. Modern oils just sort of dry up and mostly disappear, so they don't add enough drag to stop the watch. The do last longer, but it's a double edged sword because watches will run and run after the oils are gone, leading to pretty severe wear.
Living with mechanical watches was very different back then...
Cheers, Al
