FYI: OEM Battery Life
 

FYI,

My orignal battery (AGM) is approaching it's 8th year of service (it will be 8 in Jan/Feb 2014). 62k miles on the car.

1/2007 build E70 3.0si.
Nav, Heated Seats, Rear Entertainment, rear climate (power accesories)

The battery on my car is stamped with 05 07 which I'm estimating is a 5th week of 2007 battery.

Congrats, sort of.
I rec'd a new batt, a slow maintenance charge on that new batt for a day or so, and then install that new batt: on your time/at your convenience, vs it dying at the least opportune time.

And, I think E70s need to have their new batts 'introduced' to your car's BMW fine system of electronic gobbledy gook.
GL, mD

Battery life is grately influenced on how you use your vehicle.
If you drive the vehicle daily the battery will have a longer life vs. driving and letting it sit which decreases the life since the battery is not maintained on a regular basis. My 2009 battery laster 3 years. Also climate has a big impact. Here in florida batteries tend to last 3 to four years max. The heat eats them.

You are correct, The battery in my X5 is the original and it still have a lot of life in it. keep in mind I drive my X everyday.