My own definition of transgender (as I apply to myself) is that I always will be transgender. I was born physically male, I was socialized male. I am changing that to match my internal identification. What I change does not negate or remove where I came from. Thus, I will always consider myself transgender .. I transcended from what I was (well, eventually)
transition, as it relates to the OP, Will it end? IMO, yes. Transition as it relates to being transgender will end, for me, when I have reached a satisfactory point of change where I live my life as me, as myself, with no underlying depressions or dysphoria pushing me to change 'just one more thing'. Pushing myself to change that next thing that 'isn't quite right' to become the woman I was meant to be. I do differentiate between gender dysphoric changes to become myself and cosmetic changes of dislike. I really don't like my nose and I want it corrected .. it is not gender dysphoric, I just don't like it!!
Everyone transitions for their entire life, it doesn't end even when you're dead. Physically, as you return to the elements of which you are composed of. Spiritually, for those that believe, as you transition on to the next level of existence.