There is no limit to recall. It is possible to forget a lucid. Lucid just means you we're aware that you are dreaming. How many times have you been aware that you are waking that you forgot it?

I always tell people to work on lucidity, sleep schedule, and recall and they will keep improving forever. I would recommend checking out the dream signs and recall subforum it is jam packed with ways to remember your dreams. Dream journalling and wbtb being the two that effect recall the most (in my book). I recommend micro wbtbs, small wibtbs throughout the night to do a little journalling and then go back to sleep. It is very effective, since the easiest dream to remember is a dream that you just woke up from.