If you are a prime customer, you get a delivery date promised to you when you add the item to your cart, and it is confirmed when you check out. If Amazon takes

If you are a prime customer, you get a delivery date promised to you when you add the item to your cart, and it is confirmed when you check out. If Amazon takes longer to ship, they upgrade your shipping to Next Day so that it will arrive on time. And if they miss the promised delivery, you can call up their customer support. I don't know if it is official policy, but I've heard people claim that they got a month of free prime membership.