If at all, many people have only one whisk.
As the size of the whisk should always be compatible to the size of the pot, this normally means that the whisk is either too big or too small for the task at hand.
That’s why I recommend to have at least three whisks, one large, one medium and one small. This way, you’ll always receive the best possible results.
Also, I prefer silicone-coated whisks. These won’t damage your coated pots and pans like a normal whisk would do.
Again a recommendation from my side.
I buy my silicone-coated whisks from diepfanne.com. They sell them as a set at a very competitive price.