I always disconnect my batteries and actually take them out of the car for storage. This is so that I can store the LiPO's in the LiPO bag. I also always bring them to storage charge before they go in that bag. Short runs means they get discharged down to halfway, and long runs means they get brought up to halfway.

I'm not a racer so my bashing sessions are more than weeks apart so I play it very cautious. My batteries get stored for a while between uses.

I know that keeping batteries fully charged or fully empty is a bad thing for them, and they will start to puff eventually. When that happens, that's bad, and they should be disposed of.