I used Advantix in the past but the vet is recommending Vecta 3D now. I started using it the last few months. However, I am only using a half a tube on each girl. (Vet doesn't know this.
) On the tube it says it is ok to use if over 7 weeks. My girls are a lot older than that. I am just stating what the tube says. I live in the country in the heart of tick world myself. So I completely understand your issues!! I also treated my yard this month. Since I have treated the yard and used Vectra I have had 0 ticks on the girls.