I'm not sure.

I have had this discussion with students before, and you are right. Awareness does seem to wax and wane in both waking consciousness and dreams. When I read people's lucid experiences, it is always hard for me to picture when the people are lucid, and when they have slipped back into normal dreaming. Sometimes it seems to me like the author themself does not really remember at what point they gained/ lost lucidity.

On the other hand, when I think about my own dreams, I have no problem knowing when I was lucid or not. There seems to be a definite feeling when your brain clicks into lucid mode. I always told people when they were learning "if you have to ask, it was not a lucid dream. You will just know the difference when you experience it for the first time"

sounds like a cop out, but I'm sure everyone knows what I mean.