Heartworm Prevention, Practical or a Waste of Money?

I live in Florida and we moved down here from New England. I always kept my dogs on Interceptor, but then I learned about the herbs Wormwood and Black Walnut, which clean the dogs' bodies from all inner parasites. (Works for people too!) It does not cost me near as much as the vet..only about $7 a month for both dogs together..and I have still never had a dog with heartworms. Up north where it snows, I kept the dogs on Interceptor just during the spring and summer months and they did great. Down south you need to keep up on it more? And there are ticks more also, so it is best to rub lemon juice on your dogs when they come out of the tub and keep them smelling great. -But ticks HATE lemon! Frankly..if you learn about herbs, in my opinion,the only time you should take your dog to the vet is if it really needs to go for an illness or injury. Most fire houses have dog clinics where you can get their yearly vaccinations for FAR less than a vet, and also their licenses. Why pay so much for care that you can do at home? (And for ear infections, I have been able every time to get echinacea in liquid form at the health food store for less than 10 dollars and that works..plus put a drop or two of onion juice ion their infected ear and it has worked every time so far!) Vets just cost SO much. They try to force you to buy their products instead of saving cash by going to 1-800-petmeds, etc..and I cannot afford that! But I do take the BEST care of them. I recently had a bassett hound (They have a life span of 12 years ..around- and he lived to 3 days before he turned 16 with no health issues! Passed in his sleep. Why pay so much for what you can do naturally?