In the kitchen, you can use a whisk for just about anything. It is the ideal tool when you need to emulsify (a sauce or vinaigrette), add a bit of air to your mixture (eggs), get rid of "bumps" in dry ingredients (such as sugar or flour), integrate well mixtures of dry and wet ingredients ( such as béchamel or crepe dough), or help to break down a good chocolate evenly.
We recommend you always have a large mixer and a smaller one in your kitchen. The latter will come in handy when the amount of the mixture is smaller, such as when you prepare a salad dressing.