The other benefit with Costco is that they have an extremely generous return policy.

Some obvious stuff has different rules (electronics is 90 days, stuff like tires that have clear expected lifespans have their own rules), but it is extremely liberal. And my experience is that I pretty rarely have to use it, because while not everything is a premium product for a bargain price, they tend to ensure that the suppliers for products they sell have reasonable build quality and make stuff that isn't trash designed to fail.