Lol... those sorting and cleaning technique is exactly referring to Marie Kondo. Maybe the mangaka got her inspiration for the MC from Marie Kondo after all.
The "on the fence" box can be extended to a year, if you have annual festivities that require certain ornaments (Christmas, Halloween, Hinamatsuri.. whatever) - or you can make sure to put all of those in the "I'm using this" box even if you rarely do.
@enveratise between gal cleaning and goblin slayer, there was a corrupted little voice in the back of my head fearing that it could go south like the former