A 5½- to 6½-quart oven should serve two to four people, and we think this size will work for most cooking tasks. If you’re feeding a crowd, you might want to bump up to a 7-, 9-, or even 13-quart version. Keep in mind that the bigger the oven, the heavier and harder it will be to move around a kitchen, especially when it’s brimming with chili. When it comes to shape, a round Dutch oven will work better on the round burners of most stoves, whereas an oval oven may heat less evenly and be difficult to fit on a small stovetop. However, an oval oven can be useful for large, long roasts like a tenderloin. It will of course fit nicely on an oval burner, and it should also work fine on a large round burner for something like a braise, which you start on the stove and finish in the oven.