You can cook most food in a cast-iron pan but some foods will strip the enamel coating from your carefully seasoned skillet.
If you have any sort of environmental conscience, you'll realize this is the way. My dad has a cast-iron skillet and a Dutch oven that belonged to my grandma, and as the most culinarily inclined ...
For a long time, it was a fact in my mind that you shouldn’t spend too much money on a nonstick skillet because — unlike cast iron and stainless steel — they are not meant to last forever.