A copper pot spreads heat across the base and up the walls at the same time, so nothing catches at the bottom. That makes it the choice for slow-cooked dishes, casseroles and jam, jam makers have long preferred copper precisely because it does not scorch the sugar at the edges. All interiors are tin-lined.
The walls matter as much as the base here, which is not true of a steel pot. In steel the heat comes up from the burner and the sides stay cooler, so a stew simmers from below and sticks. Copper carries that heat around the whole vessel, and a lamb stew left for three hours comes off the flame with a clean bottom.
Two to three litres suits a meal for two or three; four to six litres a large family. Casserole dishes run from 500 ml single portions up to three litres for shared service. A lid that seats properly keeps the steam in, each product page states whether a lid is included.
Oven use is fine, but keep the oven below 200 °C: tin softens at around 230 °C and there is no reason to go near it. On the hob, gas and electric both work; induction needs a steel interface disc, since copper is not magnetic. Handles get hot, so a cloth is not optional.
Never heat the pot empty. Metal spoons scratch the lining, so use wood or silicone. No steel wool and no dishwasher, wash by hand and dry at once. Burnt-on residue lifts with warm water and a little bicarbonate left to soak; scouring it off takes tin with it. When the tin thins and copper shows through in patches, the pot can be re-tinned, and a good pot goes through that cycle many times in a lifetime.

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