[Ellie May]

It is vet and owner preference.
Some do want you to do it every three months.
Other just want you to do a fecal every six months.

Most of the heartworm meds do control some intestinal parasites.
It's whatever you're comfortable with.

Ellie has only been dewormed once as an adult (she is eight).
It was a precaution and probably wasn't even necessary.
She shows no signs of worms, but spends very little time outside.
However, her Interceptor does cover most of it.