You’re going to have to decide what territory you want your mark in. Ideally, you get a federal mark and you get the whole United States. But not all marks qualify. Let’s say I’m just a single restaurant in South Florida, in a town. In that case, I would just get a Florida mark. And finally, I guess you can rely on your common law rights. Everyone has common law rights in their marks, but unfortunately they’re highly limited. So one would look either to the federal or the state registration.