I have heard more rumblings lately than ever before about the problems associated with heart worm preventatives. I believe that most of the controversy is stemming from the more holistic approach some folks are taking with veterinary medicine.
My dogs are on Heartguard, once per month. They get the other required shots annually, including the rabies vaccine. I just feel like if I am going to trust my veterinarian, which I do, I must do what he instructs me to. And he says, monthly heartworm medication, year round. I'm sure it does depend on the mosquito population in your area. The South typically has a higher probability of a heartworm problem than maybe other cooler, dryer areas of the country.

I would suggest talking with the veterinarian you trust and following his/her advice closely.

Forgot to answer your question about flea prevention. I use Advantage during the warm months only. I have tried Frontline, but did not find it to be as effective on the fleas. And we don't have a tick problem. I also use Advantage on my cats in the summer. It can be quite expensive for four animals, especially two big dogs. You will find in reading that the holistic believers also discourage the use of this product. I'm sure there are alternatives for heartworm prevention and flea/tick prevention, but I have not taken the time to fully research it.

Sometimes, I think I take better care of my pets than I do myself!

[This message has been edited by Logan (edited March 03, 2001).]