The patrols make wide, slow circuits of the property, each of the five sets of four men making a complete circuit about once an hour. The more stationary six groups of two men each occasionally switch out one or both of their men with the roving patrols, to ensure not everyone gets complacent. In addition, every hour or so, six of them are replaced with fresh guards from inside, keeping all of the guards constantly rotated, and alert as they're adjusting to different areas.