I haven't had to jump it yet, but it barely turned over quick enough to finally start after several tries a few weeks ago. It has turned over at what seems to be a normal or near normal rate every time since then, though with a few exceptions when the starter seemed to lag for a second at first. It was 12° this morning and I had my jumper/air pump unit charged up and ready to go, but it did start thankfully.
I can tell the starter unit is not turning over normally often after the car has been sitting 9 or more hours in recent weeks. Plus when the battery was on its last legs last summer, I'd noticed the instrument panel does a strange thing when you open the door, and when you first turn the key. It rattles, and a faint white screen comes up momentarily in the screen where the odometer/MPG/MPH info can be displayed. It wasn't doing that after I replaced the battery until that morning it almost didn't start. And it doesn't do that when I go to start when the engine is warm or the car has been driven in the last few hours. That rattle in the instruments seems to be a telltale that the battery is weak.