I don't really think of transition as moving from one solid state of being to another. I don't think life is like that. I think it's more plasmic, where the experiences of our lives are unbound charged elements-sharing, colliding, and informing the whole in this big, loosely connected, rolling miasmic cloud. I don't know how you see where an element of your life has a beginning or end, and I certainly don't see how you can ever feel like transition or being trans is put behind you for good. The experience of going through this whole thing, like every other experience we have, informs, often in ways we don't even see, who we are, were, and will become.
I would say transition ends when you have no memory, conscious or otherwise, of going through it nor of being born this way and all the ways that has impacted you. That is not something I am working toward or hoping for, because we're talking about either severe brain injury or death.