Moving out without telling your room mate is disrespectful
Bill has recently decided he wants to move to the big city.
Bill wants to complete his move.
Bill tells his roommate about his plans to move out in advance.
Bill moves out in a flash, and he's gone before his roommate even knew he wanted to move.
Bill and his roommate talk about the situation until they agree on a reasonable timeframe.
Bill's roommate is forced to then move to a much cheaper place to afford the rent.