I have not updated my Navigation since i bought my Ram in February 2009, but i am going to soon. There are at least 3 new highways in my County alone, so maps are behind.
The updates are for the MAPS, the rest is POIs, points of interest, fuel stops, etc.
An update usually cost $199 each time
I just received a letter from Chrysler, the letter reads that my update will only cost $149
the HB is for the Harmon Becker Navigation, i don't have the new Garmin Nav