1 . after you set a address to go , it will suggest you a route . when you drive out of the route , it will recalculate a new route from you current place to the destination . 2 . after you set a address to go , it will suggest you a route . it might be far away . on the high way you do not need the GPS , so you can turn off the unit . when you be close to the destination you can turn the gp on and select view the map . it will continue the route . after 4 year , I be still use it . this be one more thing I like it . that make I trust Garmin .