You have the all-round-chef's knife for 80% of your kitchen tasks. But what about the other jobs? A petty for smaller, herb and shallot tasks; a slicing knife if you are carving fish and meat; and a nakiri to make veg prep a breeze. There is also a lot to be said for getting some extra knives just for fun - they are objects of beauty and we are not going to deny that collecting gets quite addictive!