I usually leave it on at home, then forget to turn it off when out and about. As you suggest, it's better to turn it off when not used, and it will draw down the battery when it's not needed. If you can swing it, it's not a bad idea to have at least a home charger and a car charger. My battery usually lasts about a day, so I'm in the habit of plugging it in at home and in the car.