Advantage is what I use and I only use it as needed. There is no reason for them to be on flea prevention in the winter in our states where it is cold and there are no bugs. If you want to keep her on it monthly you will probably still need to keep her on it in the fall at least sept and oct since its warm then. Like I said I only do it as needed but I do it in Oct every year because thats our last warm month so I know they are taken care of brfore winter |