How long does your Optima battery last?

I have one that's been in service for 7 years. Since the car sits alot I hook it up to a battery tender and that seems to work.

That said I just got one for another car that died in two weeks. Showed a full charge on a voltmeter, but still kept demanding more juice from the charging system. After changing all the usual suspects with no fix, the battery dealer did some more in depth testing and found one faulty cell. The replacement seems to be doing fine, but they gave it a good charge on an Optima charger before I took it away. it took two days for the charge!