Xplainsit

The answer to this question depends on what you are trying to accomplish. If saving money is what you are after then no you should turn it off when you gone. I will explain more.

The reason it is cheaper to leave your air conditioner off while you are gone has to do with a few different things people don't normally know. The first is that an air conditioner is on or off. There is no such things as "Making it work hard". An air conditioner transfers heat out of your house at a set rate and then turns off until enough heat finds its way back into your house. The second main reason is that the bigger the difference between the outdoor and indoor temperature the fast the heat will transfer to the inside of your house.

So if you leave you ac while you are gone it is going to constantly cycle on and off transferring heat outside of your house and also making the temperature difference more between indoor and outdoor.

The opposite would be leaving it off everything you are gone. While you are gone the ac won't be running at all, and as the house warms up inside less heat will be transfer to the inside. So when you get home the ac might have to run a long time to reach the temperature you like but it will overall use less energy for the day. The downside to this method is it might take hours to reach the temperature you want and a lot of things in your house will take a while to cool down, such as mattresses, and couches.

The third option is to find a happy medium in the middle somewhere. If you like to set your as on 75 then while you are away setting it so 8o might be a good option. It will save you energy while you are gone and shouldn't take that long to reach your desired temperature when arriving home.