I use the cheap Costco brand to and they really only last a few years, 5 at the longest. I do not treat them all that well so I'm sure they could be coaxed along for another couple of years with a proper charger and a more regular charging routine. I'm curious to know what life others can squeeze out of the Kirkland batteries. I only cruise locally; if I was venturing farther afield I would be more tempted to make a bigger investment in my charging and battery setup.