I agree. It's just like a spare tire. What good is it going to do if you don't check it regularly. Good news is, that JumpSmart really does hold its charge. Even though it is recommended to check it and recharge every three months, I can tell you that is overkill. I threw a fully charged JumpSmart in my car in October, forgot about it during our cold Chicago winter, and didnt need to use it until April. You would think with the -20 weather we had here, that the JumpSmart's battery would have drained a substantial amount. However, when i turned it on after that long winter, the JumpSmart still showed 100% battery life and turned over my 5.0 with ease like it was a weed wacker engine.
As for the car charger, you can certainly leave it plugged into the JumpSmart, as long as your car does not keep the outlet on at all times, even when the engine is off. If the outlet turns on only when the key is in the on position, then it is okay to leave the JumpSmart plugged in.