If AAA did a test on your battery and says its fine, then it probably is (for now). Some cars, after sitting for awhile, seem to drain batteries faster than others. I have an old bmw that if it sits more than a week without being started the battery will be dead. I also have a 96 subaru that can sit for months and then start the car just fine. Sounds like your car is more like the former, and I’d suggest getting a battery tender (you can get them at sears for $20) or disconnecting the battery terminals if it sits for a really long time. Also of note, a battery will hold a charge even in extreme cold weather (although it mey not be enough to turn the engine over…) and won’t ruin a battery. BUT a totally discharged battery will freeze in cold weather and be ruined. Battery life is limited to about 6 or 7 years anyway though, and my opinion is if yours has been discharged in the cold weather several times now your battery is close to toast (assuming its as old as your car). Go to Sears, get a new battery and tender while you’re there. It will be money well spent.