I read Ed’s post on alternator failure and wanted to throw this in. I also had an alternator failure coming from Beaufort SC to Chattanooga. Well, not really a failure but a drop in volts to 13.5 causing flags. It was fluctuating between 13.5 and 14 at first, then 13.5 for remainder of flight. My question is, wouldn’t the brushes, as in my case, start producing less and less voltage over time as to giving us a heads up about alternator replacement? Mine had 930 hrs and was a denso. I could have replaced brushes, but felt a new one was in order.