In case you are ill at yelling at Siri or pulling over to look for a vacation spot, then an onboard Garmin GPS update could be wildly useful for you. All you need to do is to say where you want to go, and boom you will be on your way. A GPS device should essentially have a current list of all mapped roads and highways on the globe in order to be effective and help its user. A Garmin Map Update needs to be done from time to time. What if a scenario occurs where your GPS starts taking you down a road which twists and turns and you end up finding yourself at a dead end? That would be horrific. Hence it is very important that you keep Updating Garmin GPS.