I was just reading this thread the other day thinking to myself that I have had a good run out of the battery in my X5.
Loaded the car up on Christmas eve to go to the in-laws, turned the key and heard ‘click’.
The car had been driven a couple of days prior with no hint anything was wrong with the battery.
Long story short, I now have a new battery but the old one (original) lasted 9 ½ years which I think is exceptional.