Do not reuse an address. Really bad practice with that.

Is the main misconception that using an address multiple times creates fewer UTXOs than using multiple addresses for each payment. However they are the exact same. If you receive 5 payments to a single address, you will have 5 UTXOs. If you receive 5 payments to 5 different addresses, you will also have 5 UTXOs. To a coin selection algorithm, these are the exact same scenario: 5 UTXOs of the same size with the same size requirement for spending.

Most wallet software will already be generating new change addresses for you. There is no need to do that manually unless you are using some ancient or poorly written wallet software that does not. And in that case, you should use a different wallet software.