i used to give my GSD greenies rarely, just when she had dog breath from eating god knows what on her walk. they are expensive, and so i saw no reason to give them to her every day. but as she got older, her teeth became stained, and she rally hates it when i brush her teeth. i can do it, but it is always a struggle. so last year,i started giving her one greenie every day, and the stains have mostly disappeared from her teeth. an older dog's quality of life can be very much affected by tooth decay, so i am glad to have found that greenies work so well to clean her teeth.