Usually I stay in the right lane unless passing, except for the highway going into/coming out of the town my parents live in. There's no shoulder on that stretch, just curbs/grass like in town, so when you're in the right lane you're very near the curb.. It makes me nervous to be that close to a curb at 55 mph. Also, the turnoffs for Walmart and McDonald's are in the right lanes. So on that stretch I drive in the left lane.