Don't sweat it, seriously.
I've done well over a hundred transactions with Amazon, Amazon UK, Amazon France, Amazon Germany and Amazon Canada. Number of transactions that never arrived: ZERO. Even when my shipment was delivered to the Cubao P.O., and the post office burned down before I could pick it up, the item was replaced and I received it.
Just be careful about asking for replacements for orders that seem very delayed, since like I said, you'll end up with duplicates. There's a limit to how often they'll indulge you. One PinoyDVD member learned the hard way that they were actually keeping track of the number of times he requested replacement orders for delayed packages that eventually arrived. Amazon cancelled his account, telling him he was poor risk for their company. No appeals were entertained; even when he got his sister to order for him with a new account, they noticed the address and refused to accept the order.