We have a friend who has two miniature dachshunds and she uses just one littlerbox for both of them. She said she just has to clean it more often. But those two - even though one is a smooth coat (Daisy) and one a long hair (Rosebud) - you would swear they are sisters. They just get along so well - no fighting at all.

So if you do have any kind of territorial question, definitely go with two litterboxes.