To shoe or not to shoe? I have asked that question more than once—usually while someone already had one foot halfway through my front door.
In my house, the footwear question comes down to cleanliness, comfort and the people coming through the door. Some households happily wear shoes indoors; others treat the entryway like an international border for footwear. There are practical reasons for going shoeless: shoes can track in dirt, moisture and whatever mysterious substance was on the parking-lot pavement.
There are cultural traditions behind it, too. In Japan, for example, removing outdoor shoes before entering the main living space has long been customary, helping distinguish the outside world from the clean interior of the home. Similar customs are common in many Asian, Scandinavian and other households.
My conclusion is simple: in my house, I make the rule; in someone else's house, I follow theirs. When I visit, I watch what the host does, look for shoes near the entrance and ask when I am unsure.
That is where I landed: good manners, unlike muddy footprints, are always welcome inside.