wow finally a reply that was easy to understand , great thanks go to you sir !Short answer, leave the full database off.
Long winded answer explaining why, if you are interested:
If you have created Favorites Lists, you can leave the full database off, assuming that the only stuff you want to monitor is in the Favorites Lists. If you have the full database on, you will "double scan" those things in your Favorites Lists, once through the Favorites Lists and again through the full database.
The full database is good for finding "new" stuff or when you may be traveling in an area and you do not have any Favorites Lists.
You will enter a location via the keypad on your scanner. The purpose of the GPS device is to update your scanner to its exact location even overiding the location you enter. The scanner will then turn those "things" on the are appropriate to your current location as well as turn off "things" as you leave an area. This feature is very helpful when traveling into areas outside your home area.