Software upgrades for your GPSr
It is great that you can upgrade the software (firmware) in your GPSr. However, I would caution that you should only do this if: 1) Your GPS is malfunctioning and they have corrected your particular issue (read the upgrade notes to find out what each upgrade fixed/added); or 2) There is a new feature that you just can't live without.
Otherwise, if anything goes wrong during the upgrade process, your GPSr could become a nice paperweight for your desk. Garmin may have made it impossible for this to happen, I don't know. But, in the computer world, it is very easy to kill a motherboard by doing a firmware upgrade (process gets interupted, power goes out, whatever).
Anyway, upgrade if you need to or must, but be careful!