You need to clean the coils out twice a year, unless otherwise noted by the manufactures. Some older Illinois-made Maytag had commercial condenser coils that never needed cleaning. Also some of the GE refrigerators had a squirrel cage type coil that also didn't require cleaning twice a year (check your owners manual to find out how often). I always pick two holidays, say Christmas eve and July fourth as the two days I clean my condenser coils