professorpaul wrote:
At that age, you are on borrowed time. Replace it. I had a battery on
my Jeep that was OEM, and 6 years old. I simply pre-empted the
situation and got a new one. A new battery is MUCH less than a road
service call/tow.

Also the "maintenance free" batteries seem to fail much differently than
their predecessors. The old batteries used to give a good indication
with slow cranking. The maintenance free versions seem to just quit.
After having 2 fail like that on different vehicles and hearing numerous
friends say the same I now preemptively change batteries. It simply
isn't worth getting stuck trying to get a little more time out of an old
battery.