Cast iron teapot is the best teapot for teas, it allows gradual and even heating. When Heating, the teapot will release the elements of Fe2+, which could help increase the tea flavor and is also beneficial to the health.
The cast iron teapot is sturdy and could not be damaged easily, and you could use it for lifetime.
About cast iron teapot maintaince, To clean teapot, Dishwashing detergent is not recommended. Simply clean it with water is enough.
If you are a tea lover, maybe you could choice a cast iron teapot, it will give you a big surprice.