I feel like this has to be something to do with stress and trying to work too hard at trying to obtain lucidity. Sleep is pretty much about relaxing and not worrying on what to do next.

An example was two weeks ago when I had tons of work to do and I was like, "alright, I need to put lucid dreaming on hold and just get sleep and focus on work". Somehow during that week I was lucid about every other day.

And then you have people that try very hard for a couple of months, yet they can't seem have a lucid dream. I suppose the best advice I've seen was to stop regarding non-lucid dreams as failures. Non-lucid dreams can be just as fun/crazy as lucid dreams. Just keep writing in your dream journal and relax. You can try everyday for the rest of your life.

For me, I care and create new goals and plans for lucid dreams, but a laid back approach when I go to sleep seems to work best for me.