The biggest problem IMHO with Garmin GPS units is when they update the maps, the new data can be so large, that the system has to delete things like the voices to install the new update.
Garmin's in general have very little free data storage memory. Which means after a few years, you either have to use a limited map set, or replace the unit.
Some Garmin's will use a SD/miniSD memory card for maps, voices, icons, etc - some will not.
As mentioned, calling Garmin is the only way to get solid information to help with your problems.
Full-Time 2014 - ????
โNot all who wander are lost.โ
"You were supposed to turn back at the last street."
2012 Ram 2500 Mega Cab
2014 Flagstaff 832IKBS TT