A small data point. In the last 2 years, I bought ~4 new batteries from Autozone. I recall taking 3 in on one day. Just coincidence so many came due at once among my 7 vehicles and trailer, and they aren't cheap these days. As I recall, about 3 failed within a year or so. My Battery Brain started tripping (have on most cars) and Autozone tested them as "bad", i.e. wouldn't hold a charge. I recall one was just 5 months old. All were free warranty replacement (I always buy the gold-top ones). Must have been a battery factory started dropping the ball, maybe Billy Bob on the night shift did something wrong 10,000 times. Probably not confined to Autozone since there are maybe 2 battery manufacturers in the country, sold under ~20 brand names. So far, none of the replacements have failed.
