[Ellie May]

Depends on the vet.

Some say give meds year-round and never test.
Some say give meds year-round and test yearly.
Some say it is okay to give 9 months a year and test yearly in cold climates.

I'm not sure there is a right or wrong answer.
It is possible that if your dog get heartworms while on a preventative, the company will pay for treatment. There are restrictions though and yearly testing might be one of those for some companies to pay.

I give it 9 months a year and test yearly but I think we will go to year-round and continue testing. Since it takes 6 months for the worms to go to the heart though, I never understood yearly testing. Couldn't it be too late by then? I'm not sure anyone has a good answer on this so I just go with a fair protocol.