I walk them at the same time, on two leashes. They have it pretty well worked out, although we often end up with one rather "braided" leash, but they don't seem to notice. with moving to the city, I will take them once a day together, and then just Sherman for two reasons: 1) He could use some extra walking to drop a couple pounds, and 2) We need to practice his leash manners. Car to parking lot hasn't given him much experience, and he's about to become a city dog.