Turning the AC to Auto, or on and off manually while at home?

Good morning!

Had a quick question regarding utility bill/electricity. My wife and I leave our AC off during the day with noone home obviously, but my question is in regard to when we are home.

Does it save us more money to turn it on auto, or for one of us to turn it on manually, and then turn it off when it gets to our desired temperature, then turn it back on when it gets warm again?

Our son is going to be born Saturday into Sunday as well, so not sure if this would change your opinion either.

Thank you!