In the best of situations, coming out is a conscious process. I think in many cases it comes down to the particular relationship we have with someone else. The telling point is whether or not the relationship is important enough that we want to be completely honest and respect that relationship. In other situations, such as employment, the realm of transition can come into play. The goal there is to head off any BS by getting your truth out there. As Rachel Maddow put it:
“The single best thing about coming out of the closet is that nobody can insult you by telling you what you’ve just told them.”
But, it also comes down to a matter of how much you want to invest in another person. While that may be true for one person, for another, not so much. While you can tell someone that you are transgender and leave it at that, they will likely have no context for understanding what you said and may fall back to whatever prejudices that they held. That’s why telling ones story can be very helpful.
However, note that our coming out is different from lesbian, gay and bisexual people. They probably won’t look any different from how people knew them, but we will. That’s the importance of thinking about what we need to tell people beforehand versus being confronted and being placed on the back foot. People need to understand that our gender identity isn’t something that happened last week or last year. It is something that has been part of who we are from the beginning.