One of cast iron's great advantages is that it's so heavy — and therefore retains and distributes heat nicely. Of course, one of its great disadvantages is that it's...well, so heavy. Along the same contradictory lines: It lasts forever with proper care and seasoning, and for some this can take forever. (Seasoning means oiling and baking the pan to give it a naturally nonstick surface.) But one big advantage is affordability: A 10-inch Lodge cast-iron skillet costs about $14, while the same size KitchenAid stainless pan can cost up to $140.

HOW TO IDENTIFY: A cast-iron pot is extremely heavy and looks as if it should be hanging in Laura Ingalls's kitchen.
Pictured: 12-inch Lodge Logic cast-iron skillet, $18, www.lodgemfg.com.

WHEN TO USE: For nonstick sauteing or cooking dishes that need to go from stove-top to oven, such as apple brown betty, potato gratin, and frittatas. Also use it if you have to fry large pieces of meat straight from the refrigerator, because cast iron will not cool. Why does that matter? "When you've lost the temperature, you've lost the ability to sear and caramelize," says John Ash, a culinary teacher and the author of Cooking One on One (Clarkson Potter, $25.50, www.amazon.com).

WHEN NOT TO USE: When you've slacked off from the gym and your arms are feeling weak. (While conventional wisdom says not to use cast iron with acidic foods because it releases a metallic taste, Ash says this reaction is barely perceptible and actually adds iron to the food.)

HOW TO CLEAN: Use a nonabrasive sponge and water. Never use soap or steel wool.