I see a fair amount of batteries that last 8-10 years. It is almost always in something that isn't used often but maintained properly. It most always something simple like an old car or truck or an old tractor. Something that has 0 draw when the key is off and is maintained better than the usual daily driver.

We had a customer come in the other day with 2 group 31 batteries that were 10 years old. He had 1800CCA worth of batteries for a 200HP mechanical injected diesel in a basic truck. Those batteries probably would have failed a test at their rated CCA years ago, but since that engine didn't need anywhere near 1800CCA it just kept going.