i know it depends on frequency of car use and what not..but on average how long should i expect the car battery to last before i think about replacing it? the car is only 8 months old.

 

There's a TSB for the older G37 where the dealer will replace the battery and a part.

A normal battery should last at least 3 years.

 

Depending on your climate a good battery may last for many years. I've had a new one last over 7 years in Texas heat before. I've had one crap out in under 3.

 

I guess it depends on the battery? I've had mine for 2 years now and it's still working fine from what I could tell

 

In Toronto, a battery will typically last 4-6 year.

 

Check the specs on your battery, it will listed on there

 

I wouldn't suggest to drain them to 0 many times, they don't like this. Happened to me before that I listen music while engine off and drained battery to 0 two times, after this I got new one because original stopped holding charge much. And that is on one year old battery.