Well, I am planning on following the Doman Method. I am going to do 3 categories, 3 times a day (Starting out this way). I know that after each day, you retire a word and replace it with a new one from every category. Well, when do you start showing a new category? After a WEEK of showing the same 3 categories? Or longer? And if you retire a word and replace it with a new one each day from every category, how many cards should there be in one whole category?