Turning off Air Conditioning when out of the house for extended time
I see a few problems with leaving the AC off for a while, depending on climate.


The AC provides dehumidification.  So if you live in a humid climate, leaving the AC off can cause issues in the house (swelling doors and window frames, cracking plaster, mold, etc).  You generally want the humidity in your house to be 50% or less.
Stress on your fridge.  If the room is too hot, the fridge will struggle to keep your food cool.  This may shorten the life of your fridge, or cause food spoilage.  (Not sure what the upper operating temperature limit is for a fridge.)
Any pets that you leave behind on vacation.  Even if you take your dog or cat to the kennel, what about your fish tank?  Will your fish be happy in >100F water?  Don't let the temp in your house get higher than what your pets can tolerate!