Dogs should be tested for worms on a regular basis, depending on their age, lifestyle, and general health. Puppies should typically have deworming treatments at 2, 4, 6, and 8 weeks old, and then every three to six months until they are six months old. After six months, mature dogs should be tested for worms at least once a year. Dogs who are more likely to become infected with worms, such as those who spend a lot of time outdoors or in areas where there are other dogs, may require more frequent testing, such as every 3 to 4 months.