I had coffee stained teeth. I got a free sample of these strips in a pack of tooth paste. I had 2 packages. I used one package both top and bottom strips the way you are supposed to, but for the second package I saved the bottom strip and used it for my top teeth, so I got three uses of whitening strips for my top teeth. I figure more people see my top teeth than they ever see the bottom ones. These strips did make my teeth a little sensitive, but it was worth it for the amount of whitening. I included a picture with this review. The top photo is the before, the bottom is the after of three strips.