will I have to keep proving my service everytime I have to do business with the DMV?
After you receive the veteran designation, it will automatically be on all of your future DMV documents when you replace or renew.
what is the refund fee we get that I heard about?
It might be the one about applying to have the Veteran Indicator added to your license, permit or non-driver ID and if you were charged a document fee, you are entitled to get a refund for the fee