Is it recommended to rinse the teapot with boiling water before putting the tea leaves in?
The main reason you put boiling water in the teapot before making tea is to heat up the teapot. You dump out the now cooler water and then add your teabags and more boiling water, and the teapot will now be warm and not leech out the temperature from within it. This results in tastier tea, but is totally not necessary if you didn't make enough hot water, or don't want to spend the time doing so.