Impossible to say. Some batteries go forever, some crap out quickly. I usually wait until the car won't start and then call AAA.

 

You can pull the battery and take it into autozone for a free extended load test. They'll give you a little graph print out of it's status, cranking amps, etc. The battery and the alternator are typically tied to gether, so when one goes it takes the other with it. Or so has been my experience.

 

When it won't start is a good time to get a new one. I'm on my 3rd battery. I also have an 06, but I am also on the original alternator.