There's another reason for Costco's appeal and trust among members: Kirkland Signature. Costco mandates that any KS product must be at least 10% better in quality than the leading national brand it replaces and/or cost less.

That further helps simplify shopping and decision-making and resolves the paradox of choice. Instead of having to sort through a wide variety of unknown brands on Amazon, they just go with KS.

https://www.thestreet.com/retail/costco-reveals-why-kirkland...