I am not talking about these fancy enamel coated things from France that cost so much money. These may be fine for cooking at home in your oven in the kitchen. What I am interested in are the black cast iron things that pioneers and cowboy cooks used and still use.
And there are two sorts of black cast iron ovens. One is smooth top and bottom and is intended to be used inside your oven at home. The other has legs on the bottom, and a lid with a rim to hold hot coals that you place on that. This is called a "camp oven" and is what I am talking about.
I just received my second dutch oven. A Lodge 10 inch deep, 5 qt camp oven. A camp oven has legs and a lid with a rim that will hold coals. This is model L10DC03, where the "D" stands for deep.
I may add to this an L10C03 which is a 4 qt oven. This more shallow oven is sometimes called a "bread oven" as the hot lid will be closer to biscuits for example, helping cook the top side.
I also have a small oven, the 8 inch 2 qt model. To my surprise there is an even smaller oven, the 6 inch 1 qt model.
I have enjoyed cooking in Lodge Dutch Ovens for more than 40 years. I have owned as many as 25 Dutch Ovens when I used to cook for groups of up to 500 people. I agree that the 1st oven should be a 12 in. 6 quart. The second, a 10 in. 4 quart and the third a 12 in. Deep 8 quart. This will allow you to easily cook a main course, a side dish and a dessert for groups of 6 to 12 people, depending on what you cook.
Tom's Dutch Oven Info / email@example.com