For many, retirement is a time to pinch pennies on everyday expenses. It might help explain why retirees are so fond of Costco. Research shows that older shoppers tend to prefer the discount warehouse club over popular retailers such as Walmart and Target. Further, baby boomers — there are about 74 million of them alive today in the U.S. — are more likely than millennials to renew their Costco memberships, which run $60 to $120 a year. As a boomer and regular Costco shopper, I’ve learned over the years that some of the best values can be found in the warehouse club’s own Kirkland Signature line of products. In fact, one in five products on Costco’s shelves carry the Kirkland brand. Many of these exclusive items hold unique appeal to retirees as well as near-retirees like me. Oh, and don’t let an empty nest discourage you from buying in bulk. Check expiration dates, stock up on items with long shelf lives, and remember that a surprising number of foods can be frozen. Take a look at our list of retiree-friendly Kirkland products from Costco. In 2016, I first explained “Why I Bought My Prescription Glasses at Costco,” and since then I...