Your air conditioning unit should be checked at the beginning of the summer so that it can provide you with cool air all season long. Don't spend money if you don't have to. Try all of these tips first and then, if you absolutely have to, call the A/C guy out to make sure your unit is still working. It may be that you need a new air conditioning unit entirely but you'll be glad you bought one when your house remains cool as the days get hotter and hotter.