Puppies should generally be wormed every two weeks from about 2 weeks of age until they are 12 to 16 weeks old. After that, worming is typically done once a month until the puppy is about six months old. Beyond six months, most dogs are wormed every three months as part of their ongoing routine health care. Worming schedules can vary slightly by product and vet advice, but a common protocol is:

• Start worming at 2 weeks old
• Repeat every 2 weeks until 12-16 weeks old
• Then monthly until 6 months old
• Then every 3 months for adult dogs

This schedule helps clear any worm larvae or eggs that are in different stages of development so the puppy stays healthy. It's important to use worming treatments that are suitable for the puppy’s age and weight and to consult a vet for specific guidance and product recommendations.

In summary, worm a puppy every two weeks until about 12-16 weeks of age, then once a month until six months old, then every three months thereafter.