A lot of times I'll get a new battery around four years keeping the old one and trading in a junk battery.
So, I was checking out prices and my daughter says, already? We just replaced the factory battery on the 2008 Malibu.
I think I would have been concerned around five or six years old. YMMV.
That's my little girl. Get the maximum out of the things you own. Waste not, want not.
I had to get the car jump started again this morning, despite having been on the charger all night. I drove it to NAPA, and tested the battery. No good. I installed this one in March of 2016.
They got me a new one, and I swapped it out. The good news? My friend, the store manager, wouldn't let me pay for it. Free battery, FTW!!