What your a/c guy is thinking:

Its always best to have a A/C tech out twice a year to make sure that your ac is running to the best it can be, usually spring and fall (before winter and summer when your going to need it most). Regular check ups will minimize any surprises for the near future, and if gone untreated can be quite costly. So its important to get checked regularly

 

Change your filters frequently- a dirty filter can cause higher electric bills

 

When its 99degrees outside and your trying to make the inside of your house 72 degrees, your a/c unit is now working overtime in the heat to cool your house down. (think about it this way picture yourself on one of those bikes with the belts attached to a motor to keep the fan moving and its your job to keep it moving by riding that bike... You would be done after 30 minutes.) your a/c can't do it either day and night everyday. Best advise drop it down at night when its cooler outside and its not over working your unit. Bring it up to about 77 in the day, its hot I know but its better on the unit. If your working all day you wont even feel the heat. Set your thermostat to get colder about 30-60 mins before you get home, but dropping it down at night should keep it cooler in the morning for awhile.