I have used Advantix in the past. My opinion of it was so-so, and I found it troublesome to put on - never fully confident that I got it properly and durably applied. This year I tried Bravecto, which is good for three months for the tick species (wood/dog and deer ticks) here in Nova Scotia. It's a large edible tablet. The dog eats it with gusto (surprise surprise - ya I know, Lab's will eat anything!). More importantly though, for me, IT WORKS. It kills ticks in less than 12 hours. Lyme disease takes 24 hours or more of saliva exchange into the bloodstream to infect dogs (this is my main concern here). By making the ticks die, dry up, and fall off in 12 hours, this removes this concern. The other nice thing that it removes is the concerns that ticks will simply be repelled and fall off in my house, wehre they might attach to one of us, and more important, they freak out a certain someone who I share the house with who will then freak out and launder everyting in sight! I know it works because we booked a vacation this spring for trout fishing in an area of high tick abundance right in the middle of the spring bloom of wood ticks. The dog got quite a few bites, despite our best efforts. Ever tick that we found on her was either dead or dying. Most of them we found dried up and dead on her pillow. So I know I sound like a salesman for Bravecto, but I'm not! LOL Just use it. You'll see!
Cheers,
-Dave