I had bought a scraper long time ago. Some tough residue is difficult to clean off the ceramic hob, and the scraper is the best tool for this task, as it takes only seconds to do the job. The blades are very durable, they last for about a year. You can use them for longer, I am sure. But because I have been using the scraper with blade for other domestic tasks, like taking the paint off the glass, etc, the edges have become rough. So, I bought these to always have a blade with perfectly smooth and sharp edges, so I do not scratch the surface of my hob.