I can only voice my own experience in this matter, but here goes anyway:
I started HRT with no consent whatsoever. The whole reason I hadn't transitioned younger was because I didn't know about HRT. Before that, I had (wrongly) assumed that I'd never pass because my body was so big and so masculine, so I didn't even bother looking into it. Then in December of 2012, I discovered this site, and discovered Youtube transition timelines, and I was completely blown away, because there were people with way more masculine features than me who ended up looking completely gorgeous. I realized that the only reason I doubted that I wanted to be female was because I was scared of what other people would think of me, not because I was having any doubts about it myself. I quickly ran through the diagnostic criteria for someone to be trans, and when I fit every single one of them, I knew I couldn't wait any longer, I had to get on hormones NOW. Especially after reading all of the accounts of people who said that HRT was basically the best thing ever.
So, after doing research on what the correct dosages were, I started hormones on my own, via internet pharmacies. And within a week or so, I already knew that I could never go back.
About a month later, when I finally got on my company's health insurance policy, I went legit.
I had to start on informed consent because, again, I wasn't willing to wait. So my doctor wrote me a temporary 3-month prescription to bridge the gap, and told me that the next time I came, I'd have to bring a letter from a therapist stating that I "wasn't crazy."
I REALLY like the method that my therapist used. She said that if at any point I wanted a letter for anything, she'd write it, even if she disagreed with me. Because she believed that it wasn't her place to tell me what I could and couldn't do with my life, even if she thought I shoudn't. And I really like this method, because it made me free to be COMPLETELY honest in our therapy sessions, because I was never scared of having to be "trans enough" to get a diagnosis. Because even if she didn't think I was trans, if I really wanted the letter, she'd give it to me. So I didn't have to pretend, didn't have to hide anything, and so she was able to truly help me. She's been a friend and guide through this whole process rather than a gatekeeper standing in the way.
Now, while I'm really glad that I was able to get hormones so quickly, because I really was at that point where I wasn't willing to wait any longer, I don't recommend this method for anyone else. I went through all degrees of hell transition-wise because I was naive and uninformed at the beginning of it, so I was constantly caught up in my own head about what every single little emotion meant to my life as a whole, and I'm a chronic overthinker, ruminator, and panickier. Before I finally started going to therapy in mid-March, my moods were just all over the place, constantly going from elation to severe depression because I was trying to use how I felt as a measure of whether transition was right or not. It took that official diagnosis from my therapist (which I did get after 4 sessions,) before I finally started accepting myself as trans and calming down a bit. (And even after that, I still went through an absolute hell of emotions due to being fired from two jobs.)
So yeah... I like my therapist's method. Take the pressure off, be willing to write the letter no matter what because it's not their place to tell an adult what to do with their own life, but always be there as a guide. Because doing it completely on your own can be a pitfall of emotions and assumptions. So having an experienced professional there to guide you makes a big difference. I'm glad I went to my therapist instead of continuing to self-medicate. I put myself through a hell of uncertainty because of trying to do it on my own.
In regards to SRS, I don't know. I used to think that HRT was enough, but now I realize I do think that RLE might be a good thing. Because ever since going full-time, my genital dysphoria has greatly diminished. Pre-transition, I was obsessed with SRS, thinking of it as this ultimate validating female thing that was the one thing I couldn't have, and wanted more than anything. Now that I've been full-time for 4 months, it doesn't bother me as much. Now that I'm not looking for that silver bullet that would assert my femaleness once and for all anymore, it's not as pressing of a concern. I do think I still want to get it, but I'm glad that I wasn't able to just rush into it.
I don't think a set period, IE the "one year" requirement is necessary, I think it's more a matter of when someone reaches the point where they're settled enough transition-wise to be able to make an objective decision, which could be as short as a few weeks for the very self-assured, or years for those who are still having social doubts despite being full-time. IMO it should depend on whether the individual is mentally ready for it or not, time notwithstanding.
Again, I don't know how this plays into the overall picture, though. This is just my experience. I know there's a lot of self-medicators who are probably completely emotionally stable and don't see therapy as anything other than getting in the way, a lot of people over on
Eunuch.org with severe genital dysphoria who wish they could have orchiectomy/penectomy/SRS available without the need to be female socially, and likewise there's people who probably don't do their research as thoroughly as I did, who might need that gatekeeping to make sure they're not rushing into a decision that they'll regret, or using the wrong dosages/prescriptions and doing harm to themselves. I don't know.
True informed consent worked pretty much perfectly for me, so I'm all for that.