How often knives need to be professionally sharpened depends on the type of knife, the use, as well as the frequency of use.For the average home cook, we recommend sharpening your knives twice a year. A clear sign of your knife needing professional sharpening is that your honing steel or slide-through sharpener at home only have limited effect, and that slicing (e.g. a tomato) becomes tricky. Your knives should cut easily and smoothly through a tomato or chicken filet without force and without any compressing or shredding of the produce.