I'll chime in on the battery depletion issue, because when I was researching the different systems, I found that it seems to be a bone of a contention and certain literature actually implies it means something it doesn't.
The short answer to how much of a pain it is to keep up with is: it's nothing to even bother worrying about
at all and, to my mind, it's absolutely impossible to do it by "accident."
Now, the longer answer to explain that......
Over-discharging the battery does not
mean running the system until your battery is dead and the SCS won't turn on. You can run any of the SCS systems until it shuts down from a "dead" battery, as many times as you want, and have no long-term problems. Even when a battery is dead to the point that it won't power whatever device it's in, there's still a few volts of power left in it. Over-discharging the battery happens when the remaining few volts drain from the battery and it hits a true 0 volts.
If you think about
it like your car's gas tank - when you get to a certain point, your gas light comes on and tells you that you should get gas. If you ignore it, you'll come to the point that your car is "out of gas" and it can't run anymore. However, if you were to pull your gas tank out of the car and dump it out, you'd find that there's still a little bit of gas in the tank. It's not enough to make the car run, but it's not truly empty either. If you left your car sitting for an extended period of time without putting gas in the not-quite empty tank, that little bit of gas that was left will slowly evaporate and dry up, THEN your tank will be truly empty, dry as a bone.
To over-discharge the battery in the Medtronic systems, you have to run the system until it shuts down and then not recharge it for a minimum
of 60 days. For the Eon Mini (ANS), you have to run it until it's dead and then it has a 90-day reserve before the battery is considered over-discharged. Over those 60 or 90 days, the last bits of power in the battery run out until it's really, completely, totally dead. Beyond that point, you'll usually need assistance from your rep to re-power the system, because when it hits a true "dead" battery, the programming will usually get thrown out too.
I'm not sure what ANS recommends as far as replacing the battery if you over-discharge your unit multiple times, but Medtronic recommends replacing the battery if you over-discharge it 3 times. That amounts to leaving the battery sitting dead for a minimum of 60 days, on 3 separate occasions. That's a total of 6 months
worth of dead battery and not using your SCS. Of course, they also recommend considering explantation of the system at that point because if a user runs the system dead and leaves it that way for such extended periods of time, then it's highly unlikely they're getting adequate pain relief anyway.
If you have a legitimate reason for not using the SCS for an extended period of time, such as pregnancy or long-term illness, then you just have to make sure the battery is charged when you turn the system off.