Only for taste. I know many people who sit down to a meal and the first thing they do is reach for the salt (and pepper) before they even taste the food. But, since I do most of the cooking at home, I already know what the seasoning is like. (My wife has high blood pressure, so I generally don't use a lot of salt if I can avoid it.) I think you always need to at least taste what the cook presents you. Then, if you personally would like to adjust a little, go for it.