My husband very graciously volunteered to try out this product to color away some of his grey hair. He mostly has grey hair on the sides of his head so we although we applied the color to the entire head, we concentrated a little bit more of the solution on the sides. It was easy to mix the two solutions and the smell was not as strong as the ammonia smell I am used to from generic products we've tried in the past (the kind you can get from beauty supply stores). The wait time was pretty short at 5 minutes. The results are good - subtle color that almost completely got rid of the grey and replaced it with his natural light brown hair color. Overall the product was easy to use and the results were exactly what we were looking for - nothing too dark or drastic. I would recommend this product to others seeking similar results.
I've been using this product for a few years now, and am pleased with it. It's easy to do & looks good. From my experience, each application lasts 5-6 weeks. Just be sure to wear the gloves, follow the directions, and try to avoid getting it on walls, the floor or other surrounding areas. It will stain!! I have gotten into the habit of covering my sink area with paper towels before I begin.