pay rent to keep right to hold an NFT

RentNFT.sol

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity >=0.8.0;

import "https://github.com/Rari-Capital/solmate/blob/main/src/tokens/ERC721.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";
import "https://github.com/Rari-Capital/solmate/blob/main/src/utils/SafeTransferLib.sol";

contract RentNFT is ERC721("RentNFT", "RENT"), Ownable {
    using SafeTransferLib for address;

    mapping(uint256 => Rent) public rents;

    struct Rent {
        uint64 start;
        uint64 term;
        uint64 due;
    }

    // ** RENT LOGIC ** //

    function payRent(uint256 id, uint256 amount) public payable {
        Rent storage rent = rents[id];

        rent.due = rent.due - uint64(amount);

        owner().safeTransferETH(amount);
    }

    // ** RENT MGMT ** //

    function setRent(address to, uint256 id, uint256 term, uint256 due) public onlyOwner {
        if (ownerOf[id] == address(0)) {
            _mint(to, id);
        }

        rents[id] = Rent({
            start: uint64(block.timestamp),
            term: uint64(term),
            due: uint64(due)
        });
    }

    function retrieve(address from, address to, uint256 id) public onlyOwner {
        Rent storage rent = rents[id];

        if (block.timestamp > rent.term && rent.due != 0) {
            require(from == ownerOf[id], "WRONG_FROM");

            // Underflow of the sender's balance is impossible because we check for
            // ownership above and the recipient's balance can't realistically overflow.
            unchecked {
                balanceOf[from]--;

                balanceOf[to]++;
            }

            ownerOf[id] = to;

            delete getApproved[id];

            emit Transfer(from, to, id);
        } else {
            revert();
        }
    }

    // ** GETTERS ** //

    function goodStanding(uint256 id) public view returns (address owner, bool standing) {
        Rent storage rent = rents[id];

        owner = ownerOf[id];

        if (rent.term > block.timestamp) {
            standing = true;
        } else {
            if (rent.due != 0) standing = false;
        }
    }

    function amountDue(uint256 id) public view returns (uint256) {
        return rents[id].due;
    }

    function tokenURI(uint256) public override pure returns (string memory) {
        return "RENT";
    }
}