Reiterating that you never know where the point of "little to no return" is. After a month my voice had dropped enough that I was getting correctly gendered in person 80% of the time. Around two months or so it was all the time except at drive throughs and over the phone. Probably three to three and a half months or so in, I never get called ma'am anymore, and my jawline has changed enough I probably wouldn't be able to go back, even if I could even GET my voice into a falsetto range, or higher than "gravely" lol. Four and a half months and a small beard is showing and I'm getting a "dirt 'stache" Which looks ridiculous so I shave it off lol, but yeah, that won't go away. The muscles started happening around three months, but at that point I still couldn't have gone back. My younger brother and I pass for twins at this point, can answer the phone for each other, answer the walkie talkies at work for each other, and just confuse the crap out of people in general. It's highly amusing, but he's cis, and I'm trans. For me to be gendered exactly the same as him, nearly down to the age that we get guessed at (we both look way younger than we are) and only four months, it's a lot of guesswork.
If you get a side effect you don't want, how would you handle that? (if you did run into my brother and me, look for the tattoos lol. Ours are different, obviously, and his muscles are bigger than mine, though not by much. :p )