Hey, I just wanted to agree with Swe that you can lose lucidity. I've had dreams before where I've realized that I was dreaming but have been so caught up in the current dilemma at hand that I've forgotten I was dreaming again. It's a very annoying feeling and it does happen from time to time, not very often though. The more common thing is that you become less lucid but are still aware. I define perfect lucidity as being just as mentally awake as you are in your waking life. You should be able to remember what you ate for lunch, or dinner the night before, where you're currently sleeping, things like that. That's perfect lucidity. Sometimes though we might be at 80% and slip back to 20% and so on. This happens to me fairly regularly.