The exterior part of your Central A/C unit needs regular attention to insure birds or other wild life have not built nests that may clog or reduce air flow. Early Spring is the perfect time remove debris and clutter that may have accumulated around the unit and examine it for signs of wear before plants and shrubs have a chance to block your view. You will also want to keep flowers and shrubs back a few feet to allow for maximum air flow. To help keep the unit cool, make sure it is not in direct sun light. If you have a direct sun light situation consider placing a decorative trellis of fence around the unit to help shield it. And don't forget to run it for a short time while it is still fairly cool to make sure it is working properly. If service is needed you'll have a big jump on it.