It’s not necessary for all of us. I purposely took EV injections only without Spiro to see what my body did with just that, blood levels- wise. If it didn’t bring my T levels down, then I would plan toconsider Spiro. As it carried more risks, especially for someone like me that has kidney stones and dehydration issues in the past. In my case, with the standard initial dosing for EV, my T crashed out by itself to the bottom of female ranges by my first post-HRT blood test. I’ve since about halved my dose, and nearly two years later, I’ve never seen my T levels rise, and E2 has been in “ideal” ranges.
IMHO, start EV injections first, see what your blood levels do, and address with Spiro later, if you can’t get T down. I had two different doctors, both supporting this approach when I suggested it as risk avoidance.