We have been dealing with ticks for 3 years since we got our first dog. We live on beachfront and my dogs love to go to swim in the ocean, they go daily. So forget about all the kind of shampoo and drops that you can imagine, we have tested them ALL. Hopefully, couple of weeks ago we found an injection to do to the dog, and as a miracle since then no more ticks ;-) I'll find the name of the product, you have to inject it once a month and so far, so good, hope it lasts...
I've had several dogs in the DR and some of them attract them like magnets and others are almost immune.
One of my dogs, Rocky, I had nicknamed the Tick Hotel.
It was a constant battle,
Bruno, the Ridgeback I now have, never gets them.
I have used Frontline shoulder drops with great success, but known friends who said it would not work on their dogs.
Injections can be an option, and also works most of the time.
What I now do, is send Bruno to the Pet Lodge once a month, where they bathe him with special shampoo, give him his necessary shots, including anti tick shots if need be, and. like I said, he never gets any, but I also had a Black Lab here at one time, and she, with the exact same treatment, would get them all too frequently.
In short, what works for one, may not work for another.