Jackson got sooo many ticks on Frontline. Over 10 in a few weeks. So we switched to K9 Advantix and haven't had ONE tick since (to my knowledge).
I will never go back to Frontline.
Ticks are gross little suckers. I hate them! I also bath Jackson in Minksheen, which contains insect repellent, so that may help a bit as well.
From my understanding, Frontline will kill ticks that get on them but they will still attach. Advantix is supposed to repel them a little bit better, it also repels mosquitoes which Frontline does not. But I think certain areas may become immune in a sense. I heard stories of Frontline not being effective on ticks anymore because so many ppl use it... so I dunno how true that is.