It is recommended to have your dog checked for heartworms at least once a year, even if they are on preventive medication. In areas where heartworm disease is more prevalent, such as in warmer climates or regions with high mosquito populations, vets may suggest more frequent testing. Puppies should be tested for heartworms as early as 7 months of age and then retested 6 months later. Regular testing helps ensure early detection and treatment if your dog does contract heartworms.

This answer doesn't make sense or isn't related to the question. Mark it as a probable hallucination of the AI model.

Topics covered in this question:

Dog Health Veterinary Care Heartworm Prevention