Completeness of Preferences Economists assume that consumers have a set of preferences that they use to guide them in choosing between goods. These preferences have to satisfy three properties: completeness, transitivity and "more is better". 

By completeness I mean that when consumers face a choice between any two bundles of goods, they can always rank them. This rules out the possibility that consumers cannot decide which bundle is preferable. I am wondering how to deal with the introduction new goods? Does it mean that this property only apply to available/existing goods? And should a consumer also rank today a good that is coming tomorrow? I have the intuition that if a new good replaces an existing one, the rank of preferences may change and I dont know how deal with that. Any reference would be appreciated.
Would you like to buy a pack of sugar flavored amazonian soil for 500 dollars?

You can probably answer this question even though you have never heard of this product before. Being able to answer this question, being able to place the newly available consumption alternatives within your ranking is the assumption of completeness.

The same is true if a type of good is replaced. The set of consumption alternatives is changed, but given any two you can still tell which one you prefer.