The Kansas song is ringing in my head.
Just about every well read person on this list knows that after a certain period on spironolactone the effects on the testicles are irreversible. Also the amount of time on estradiol and progesterone can produce irreversible changes in the body through changes in the skin, musculature, gynecomastia, hair and other secondary sex characteristic changes.
From what I've been able to determine, between six and eight months is getting into the difficult to reverse time, and anything past eight months and a year is really into the "changed for life" zone. YMMV

But is this time given for only being on one medication like just the spiro or estradiol? What about a combination, or all three? Is the period where changes are reversible shorter?
I've never seen any posts from anyone that said what medication regimen they were on then stopped and how long, if ever, it took to get back to the functioning as a male.
Actually, my question is more academic than anything else, I have no intension of stopping my HRT for anything less than a life threatening reason. I certainly don't want to go back and have my masculine secondary sex characteristics rear their ugly heads any more. I'm becoming quite comfortable with my feminine secondary characteristics!

I was just wondering.
Inquiring minds want to know...
-Sandy (the curious)