Transition may be complete in terms of what we set out to do.
I consider my transition as essentially complete because I have gone as far as I need to. The only thing left would be changing my name and gender markers, but for various reasons, I am not planning to do that. My transition would defined as social. I have no interest in any medications or surgeries. Personally, I don’t believe that I have ever experienced gender dysphoria. I have never thought that I was born in the wrong body. However, what I did figure out was that I was never completely male. I was never completely female either, for that matter. What finally struck me was that I have always been this amalgam of genders. My gender expression is female as I present as DeeAnn at least 98% of the time and that is how I am known in the area where I live.
I suspect that those outside of the transgender community think at all, or at least most, trans people have medically transitioned. The reality is that only about 30% of trans people actually have any sort of confirmation surgeries.
Everyone defines what they need to do in order for their lives to make sense to them. A term that is often used is Congruence, or having our mental self align with our physical self. For each of us, transition takes the course that is specific to us and what we must do. It is not our place to attempt to define transition for someone else.