Some sort of cooking vessel is one of my essentials. Sometimes it is a cup that a Nalgene rests in, or a titanium cup that is a bit larger than 12 ounces.
Sometimes I carry a metal coffee can with a hanger made into a handle.
I generally carry a 1 quart titanium pot when backpacking.
They don't take up much room because you can pack stuff inside them, and they are light. So unless it is a pocket type survival kit that I am limited to, I am carrying some sort of cooking pot.