The battery in a low mileage car will need to be replaced sooner, not later. In fact, Porsche will NOT warranty a battery on a car unless it has been driven at least 10K miles per year (according to my service rep).
If you let your Porsche sit in the garage, the battery is one of the first things to go.
This is more so now that modern cars use a fair amount of juice just as they sit there.
