I don't wear shoes in the house but I don't think there's much validity around cleanliness
uhhhh
you definitely track in dirt and dust and whatever's on the ground outside (snow, broken glass, dog shit, road salt,), if you wear the same shoes outside and in.
It doesn't necessarily make the person dirtier but it definitely makes the house dirtier IMO. Not by like, a ton, if you clean regularly its probably fine esp if you don't have carpet, but I still am not a huge fan. The "tracking in bits of broken glass" thing actually happened to me recently. Bunch of car break-ins on my street and a few days later I start finding pieces on the ground in my apartment.
The worst part is my city is pretty clean for the US lol. But yeah snow is just unavoidable if the climate is right for it, everything's getting a bit wet at least. (unless you are a bougie MFer with indoor parking and snow removal service and basically go from house to car to office without stepping foot outside, which some people do.)
And besides a few times a year to clear grime and rotten leaves and dirt and keep the storm drains flowing, the streets don't really get actively cleaned here except by random passers by, so those accumulate some level of things like broken glass, bits of trash, etc. Dog poop is not a common problem for me, but for people who have dogs and aren't perfect at cleaning up their yards after them its much more common.
I don't know what level of street cleaning other countries have, or whether they just have a more conscientious populace, but yeah parts of the US are filthy
we get a bit of stuff like that in the central business district, but its more like low wage workers going out and picking up trash than a full sweeping of streets/sidewalks. outside downtown its what I mentioned before. to some extent its because of low density, but also just public services are a joke in the US.
I don't wear shoes in the house but I don't think there's much validity around cleanliness unless you've got a shower by the front door and are doing a full wash and change (and even then, I'm not convinced this would make a positive difference in most scenarios)
Mud and stones very easily get stuck to shoes, and tracking in water is a dick move too.