2002 TDI (ALH) with 513,000 km. First Owner and very happy... No Problems, never left us stranded on the Highway. Average useage is about between under 4 ltr. and 5 ltr. Normal longdistance travel: 4.1/100
First battery lasted 3.5 years, still on the second one. I'm already at about 3 years on this one. Battery life does vary depending on usage (TDI vs. gasser), but it also depends a lot on where you live. Both cold and hot ambient temperatures are hard on standard lead/acid batteries. Those people who claim 5 and 6 year life from batteries almost always live in temperate climates. Those long life batteries almost never come from Minnesota or Maine and they almost never come from Phoenix or Las Vegas. Here in LV we consider ourselves if a battery lasts over 3 years.
My 2010 TDI with 60K miles is on its original battery. A while back, it somehow got run down (I think my wife left the lights on). We drove the car for an hour or so and it has been doing fine ever since. We must have gotten a good one.
just replaced mine yesterday. Went dead pretty much overnight. Got the car in July 2011 and its got a little over 63k on it. My electronics went a little weird as well- my automatic windows still don't work.
5 years and 3 months, with 153,000 miles so far...and it still works perfectly. I work up at a ski resort and the car has had to start in very frigid temps each winter, with no issues. Replacing the battery soon because I feel like I just have to with it getting long in the tooth. The car won't be driven in winter anymore as I'm buying another car for that, so I hopefully get a long stretch out of the next battery!