Iron cookware is hands down the best possible metal for cooking. You can easily do any type of cooking using iron utensils, as they have zero harmful effects. Iron gets heated up uniformly and helps in quickly cooking the food. When heated up it also releases iron which gets absorbed by the food and is beneficial for our body.
You can switch to iron utensils by ditching 1-2 old utensils in your kitchen. But iron may impact the taste of your curries, so go for seasoned cast iron.