Batteries
Battery life by climate, testing, replacement and registration.
A lead-acid battery does not wear out gradually in a way you can feel. It works, and then on the first genuinely cold morning it does not. Heat is what kills it — sustained high underhood temperatures accelerate grid corrosion and water loss — and cold is only what exposes the damage that summer already did.
Three to five years is the normal US range, closer to two to three in Phoenix or Las Vegas and five-plus in a mild coastal climate. A load test tells you where you are, and most chain parts stores will do one free while you wait. See when to replace your car battery.