how to warm the teapot

I do not usually pre-heat my kyusu. But I do this because it drops the water temp to 180, which is the temp I use in it.
I do pre-heat it when I am drinking black tea because I need the higher water temperature for blacks. I think water quality and temperature have a lot to do with the taste.
I do however place boiling water in the tea pot to heat it up. I do not know of any cracks, and I have been doing it for years. But I could just be luck.

I use boiling water for my tea on a regular basis (pouring it into the pot, often without warming it first). Teapots are designed to withstand boiling water, in general. I’ve taken to warming mine lately, but I usually just use hot tap water as I’m giving it a rinse.

To me tea tastes better when the pot is pre-heated. I use a porcelain tea pot and heated it with boiling water. So far no cracks :)

I did end up with crazing in a novelty-shaped teapot many years ago after adding boiling water to it without pre-warming. It eventually became unusable. Rinsing the pot first with hot water seems to do the trick.