I have a dark granite and it doesnt stain with coffee, I was told if I
left red wine on it all night it could stain. Light colors will stain
easier. Id say if you have had no problems and dont use products that
can stain you have little to worry about, but buying a " kit" seems
like overkill, it is sold to make them money. If you want to seal it for
saftey just buy the sealer.