You should sharpen the blades on your knives every 2-3 months, depending on how frequently you use each knife. Some knives get used a few times a day, while others are only used for certain instances. You should also consider what you’re using your knives for. A bread knife only cuts soft items, while some other knives get used for harder foods, so may dull faster. It is also recommended to have your knives professionally sharpened every year or 2 if possible.