Plenty of good points made already - gas is cheap, products are good - but what keeps me a Costco shopper is the consistent and frequent stories about them being a genuinely good employer. Maybe because I've spent my career in retail IT, but I hear all the time about how good of a place Costco is to work. Staff turnover is low, wages are good, and they close for most holidays. I may not need 48 AA batteries often, but when I do, I'd rather buy them at Costco.