What is The One ultimate and the most important rule of using Yixing teapot?

Answer: HYGIENE!

~  Sterilize the teapot with boiling water before use

~  At the end of the tea session, immediately remove all the tea leaves and flush with boiling water.

~  Dry the interior of the pot with a clean and dry cloth

~ Ensure that the pot is totally dry before storing

~  NEVER  STEEP THE TEA LEAVES IN THE POT OVERNIGHT

~  Sun the pot. The UV will sterilized the pot further.

Always remember : Hygiene, hygiene, hygiene all the time. Never ever  compromise.