When we had one of the earlier heat waves this summer, I noticed that my A/C unit was not working as well as it should be. It would be 100 outside, and 80 in my apartmentl. Property Management got someone out to service the A/C unit, and thankfully they did a good job with it. The last heatwave it was 106 out, but the apartment was 73. Thank God!
I turn my thermostat to 77 every morning. Most summer days it doesn't kick in until late afternoon, if then. Lately, temps have been in the low- to mid-90s, so it's on more. I don't turn it down until I go to bed, at which time I turn it to 74, and then down a degree or two if I get up in the middle of the night.