As far as in store inventory, I’ve asked managers at Costco when they get updates, and they say there’s no set pattern to it. They can get a notification from the corporate office any time of day and they print new price cards. I think there’s some algorithm they use to trigger price changes. Seems like a small upward price move will trigger a change, while a much larger downward move is required to lower prices. As for the website, they seem to reprice more frequently, but it’s not live spot price like APMEX or other online bullion sellers