I believe there is an issue of stewardship here.
All that we have is a gift from God. We may enjoy our posessions, but we do need to give account to the Lord of how we have used them.
Carpet cleaning services are necessary to keep homes really clean, but they are very expensive. Replacing carpets costs even more. Having a shoes-off policy considerably reduces the need for maintaining carpets and other kinds of flooring. Therefore, as stewards of God's gifts, I would suggest that Christians ought to strongly consider the benefits of having a shoes-off policy in their homes.
Clean homes can also be more effectively used in the service of the Kingdom. Homes can be put to so many uses; entertaining visiting speakers, providing shelter for those who need it, hosting fellowship meetings (I think a good case can be made for holding all church meetings in homes) and Church lunches. Keeping homes shoe-free means that larger numbers of people can be accomdated at the home with minimal impact. It also makes the floor a safer place for small children and babies.