Acutally using a change address, is the way that you need to use to get your change back, so if one of your UTXO is 1 Bitcoin  and you only need to send 0.5 Bitcoin, What are you goint to use to get your change Back to you? Of couse a Change address, it can be the same of the source of a new one Address if you ask me i prefer to use a different address each time. But that depend only of your preference

In any CASE you NEED use one Change Address i mean the extra 50 bytes for the extra output will be payed even if the change address is the same than the source address.

The only way to not use a change addres is when you made a transaction without change.