Since this is my first Stingray (5H Special), How many hours can I expect from the batteries? If they die, I imagine the bass would not be usable. Is there any sort of battery life indication so I know when I should change them
More like years.
With 1 9V battery, it's common to get anywhere between 1 & 3 years life (depending on amount of use, and remembering to unplug the instrument when not in use), before it starts to deplete enough to cause distortion.
With 2 9V batteries, as used in the Specials, you can pretty much double that figure.

