I turn it down to 69 just before sleeping. I find if I set it for 71 or higher for sleeping, I have some congestion or dry throat when I wake up.
For daytime, 77-79 usually. If I come back in from being outside, or from grocery shopping, I'll bump it down to 75 to cool off from that.
Got a new AC unit 2 years ago. Bills have been way down due the effcicency of the new unit. I lived with the inefficiency of the very old previous unit for too long. I don't know why I waited so long to bite the bullet and upgrade!! I went with the heat pump option. They even wired the new digital thermostat for power. I need no batteries for it, and I leave the display lighted 24/7.