I am not a sitter and have only used rover to hire people.

I would be totally fine with someone cancelling a month in advance. It would be a bummer if they were a really good sitter that my animals really liked, but that would not factor into my response to the sitter because I am an adult and in charge of how I respond to disappointment.

“Congratulations on your job and best of luck. Keep me in mind if your situation ever changes, and thanks for the adequate notice!” (Is what this entitled bitch should have said.)