Fortunately, one of the most common reasons for checkout delays is rather preventable.
Robison said that the biggest issue employees have "is when people don't have their membership card with them."
"It can be a very time-consuming problem to fix," Robison said. "The cashiers don't actually have the ability to look up member information on the register, so we have to call a supervisor or manager over to get the member's ID."
If Costco is especially busy, that can take even longer because supervisors are likely assisting in other areas, Robison said.
It's much easier for a shopper who forgot their card to stop by the membership area when they arrive to retrieve their member number.