[cucumber3732842]

More often it's just that the situation changes with time.

Like someone will work with existing shared neutral aluminum circuit spaghetti because that seemed right when the scope was narrow. Maybe they're just throwing an outlet on the opposite side of the wall for someone's CPAP machine. Maybe they're actively avoiding putting it on the bedroom circuit because of which window the A/C goes in. Then the scope grows, circumstances change and the specialized solution is no longer optimal.

Then the next owner shows up and has to troubleshoot something and between hindsight and the smug know-it-alls on /r/everytrade (seriously, the internet is great at driving off people with wisdom and experience) they pronounce the prior guy to have been an idiot.