I'm almost certain I still have my original battery in my E53. That would make it 8 years old in May 2014. 38,000 miles on her. Time to change the battery as preventative maintenance?

__________________
Current BMW's:
2013 E70 X5 xDrive35i Premium (mine)
2014 F25 X3 xDrive28i (hers)
Past BMW's:
2001 E46 325i
2001 E46 330ci
2003 E39 525i
2006 E53 X5 3.0i
2008 E70 X5 3.0i
2014 E84 X1