trans | question about spiro

I'm not on spiro yet, just estradiol, but I'll probably be starting when I see my endo again (in a few weeks). Anyway, what I need to know is how closely do you need to watch your potassium intake while on spiro? I know it's potassium-saving and you have to be careful not to take too much potassium while on it, but just how careful do you have to be about potassium?