I use Frontline every 3 months unless ticks are bad then every month. Gavroche gets Advantix when the mosquitos are bad because he getd big red welts from them. I also get Frontline free from the Merial reps and aHave a stockpile of it. I have 6 months free of Trifexis from the Elanco rep I'll be trying once ticks aren't an issue.