How long should car batteries last?
The Kia is 8 yrs
VW is 7 yrs
Both oem
Our experiences mirror those sort of "lives". Generally the "end" comes with spells of very cold weather where the demands and a reduced amount of driving about become just too much for the reduced storage ability of the battery to cope with.
We can "limp" through those times by putting the battery on charge and waiting for the warmer times. However, finally at least in our case the reality of what has happened becomes increasingly evident and we buy a replacement, simply to have confidence in the ability to start when we want to.
Inevitably these batteries' ability to hold much energy declines, fact of life, the balancing trick is judging if it is still enough to do what we ask of it, if that task is not much, then we get a long life.
Those that situations place greater storage asks on their batteries, will not.
I recall that starter battery failure is by some margin the primary reason the AA, RAC etc report they get call outs; rather proves we don't all accept what becomes to us as the obvious, and keep on pushing their luck.