Our dwelling is a shoes-off zone.
I am from Japan where this goes without saying and Misha has lived in Korea where, also this was just the understood norm.
I firmly believe that dirt from outside that sticks on the bottom of the shoes is far more unsanitary and dirty than whatever can possibly be on the floor or carpet of a house. I mean, you don't get dog shit or some stranger's phlegm in your house. The dirtiest it can get is dust that collects and food that YOU or someone you know has dropped on the floor. The dirtiness of a house really seems quite predictable.
However, it seems that others don't feel similarly.
If our lovely black carpet (–> the slightest bit of lint shows off really well) looks the slightest bit dirty the shoes don't come off–at least from the parent who seems to believe equally firmly that what looks dirty IN the house is equally unsanitary and unclean as what is OUTSIDE. The logic escapes me, since neither of us leave our shoes on in our temporary dwelling, making the inside a lot more sanitary than the outside by definition. But, such is life.
Misha tends to clean up the place quite nicely before his parents arrive, but the place apparently still appears like a dump to his perfectionist parent. Alas. I just wish that we had a 玄関. It would make the shoes-off policy a lot easier to enforce.
Leaving shoes on in the house just seems so dirty to me!! Yuck!!!
FrinJew 
So many people in the UK wear shoes at home. It is dreadful. Shoes-off in homes is definitely the best way.
Thank you for your response and posting of a link to this post.
Yes, I agree that shoes-off in, shoes-on out is the way to go generally speaking. I feel less strongly when the floor is hard like a hard-wood floor, stone, or concrete. But on carpet, it feels very strange in deed.
Hardwood can get scratched or marked.
Also, hardwood floors do not absorb dust, unlike carpets, so if you wear shoes indoors on a hardwood floor, the air quality of your home will be poorer.