Advantage #1-
Properly seasoned you ask? What's that? Isn't that hard to do?
No. It's not. As a matter of fact, you can buy pre-seasoned cast iron from most makers now. This option adds about 15 percent to the purchase price of the identical unseasoned item. But if one wishes to avoid a smoky kitchen, and a dish or 2 out of the gate that must be carefully selected, there's nothing wrong with this choice. However, should you buy seasoned cast iron, and then flub up, requiring you to re season your cookware? That's right, you need to know how to do it.
Seasoning is basically filling and sealing the pores in the surface of the metal, and it's really simple to do. For the initial run, I recommend Crisco or similar shortening over oil, as it does a much better job of filling and sealing the porous surface of cast iron cookware.
Step 2. Rub Crisco or equivalent lightly over the entire surface of the iron ware, inside and out. You want a nice even coating, with no globs or dry spots here. Note: You may use the cooking oil of your choice for this step, but doing so may require 2 or more seasoning sessions to get the pan in question ready for its initial use.
Step 3. Preheat the oven to 350 degrees. Place drip tray under area where the pan will be placed to catch the extra oil that runs off during the seasoning process.
Step 4. Place the item to be seasoned in the oven for one hour. During this time, keep a paper towel or basting brush handy that is loaded with a little shortening or oil. Check two or three times at even intervals for dry spots on the cookware. If found, quickly brush/rub on a little more shoertening/oil. NOTE: This can get a bit smoky. Disable smoke alarms, open windows, and ventilate the kitchen. DO NOT leave the kitchen unattended. Be prepared to spend the entire hour in or near the kitchen for safety reasons.(Say for instance that you have a gas stove and used way too much grease resulting in a fire that needs dealt with post haste)
Step 5: When the hour is up, turn off the oven. Allow the item being seasoned to cool to room temperature naturally. Resist the urge to try cooling it faster by leaving the oven open or taking the item you are seasoning out of the oven all together.
Step 6: After the item has cooled, remove from oven, and check for dry/bare spots. If they are few and far between, you may start cooking with your new ironware if cooking low acid high fat foods, as the pan in question will continue the seasoning process as you cook. If there are several spots or extended areas that are still rough feeling bare cast iron, repeat steps 2-6 again.
With a properly completed initial seasoning, your ironware should have a slightly golden and smooth feeling sheen afterwords. If it is still a rough surface, or completely metallic grey in color, try again, you did not use enough oil/shortening.
With time, and repeated use, your cookware will take on that high gloss black sheen that well seasoned cast iron is known for.