NFT that is bound by time

NFTs have a unique ID and belong to a single wallet. Two standards define what an NFT is and should do: ERC721 and ERC1155, aiming to distinguish each token to be unique. The development of NFT is still in the early stage, and this research shows how NFTs can change their properties. We go through some existing solutions where some events fundamentally affect the NFT, changing its state, properties, or value. We give an overview of those solutions with a desire to cover how they work under the hood and notice potential problems. In the end, are presented possible use cases that open a new door into the NFT word.