When I first started getting serious about lucid dreaming almost two years ago I had a rather decent LD frequency, and I would often have lucid dreams about 2-3 times a week, and always at least once or twice per month.
Then all throughout year 2012 I had a consistent frequency of about 1-2 lucid dreams per month without even trying, and my last real lucid dream was perhaps four months ago - and I can’t seem to become lucid since then.
Of course, I have had several dreams where I have come extremely close, and last night I even had a dream where I started thinking “keep the dream alive…!” almost right before I woke up - but, I don’t think it counts as a real lucid dream, because it was a very lazy thought and I hardly understood it at all.
Is it normal to have a long break like this?
I know I’m not really focusing on writing down my dreams nowadays, but can skipping a Dream Journal really have such a negative effect?
Well I’ve noticed that with time and number of lucid dreams in our experience we start to take this experience and phenomena for granted. What I mean is that we try very hard at the beginning of this journey but later on we stop to try so hard not maybe because we are not motivated (although it’s often the most common reason) it’s just because we got the number of lucid dreams peer week/month in satisfactory number.
So all the rush and awesome feelings that we get of this experience while we are trying/learning to become lucid we just replace with this urge for more lucid dreams. Then we all the things we usually did FOR becoming lucid we stop doing them and we focus on thing WHILE we lucid.
As time passes we completely stop doing things for inducing lucid dreams and we focus on the lucid dreams as something we will probably experience frequently or so to say we take lucid dreams for granted as I mention before.
It this process of “falling back” we loose motivation, we loose something even more important and that is to enjoy non lucid dreams as we once enjoyed lucid dreams. This I consider one of the most important things. Enjoy your non lucid dreams as lucid ones. Once you stop feeling excited about dreams in general then LD’s will become very rare.
Well try to remember how you felt at the beginning and what you did every day and night. I bet you that you were writing DR back then and as you said you stopped doing it now, I guess that’s just one of many things that you stopped doing…
Good luck! 
Thank you, db_FTS.
I believe I finally ended this dryspell last night, or at least I experienced something that was “pretty much” a lucid dream - I knew I was somewhere else than in physical reality, and I vividly remember trying to turn on a television only by mentally commanding it, “because you can do that in dreams”.
Then I got a little annoyed that it didn’t turn on, and I believe I stopped trusting I was in a dream at that point.
But anyway, this was certainly extremely close to a lucid dream, if it wasn’t indeed a lucid dream. 
I have also noticed that the time I go to bed seems to matter a lot - if I go to bed very late in the night or even very early in the morning (it happens pretty often 
) I will feel exhausted and simply can’t seem to have the energy to remember any dreams, but if I go to bed early before I start to feel really tired I will suddenly have much better dream recall and chances for lucidity.
So maybe this can be an important factor?
Definitely, first of all because you get less sleep which means very short REM cycles which means smaller number of REM dreams which means less dreams to remember.
Also mental exhaustion plus physical doesn’t help in any way possible. Well try to get as much sleep as possible, that’s always good as for body and mind the same for dreams…
Good luck!
Yes, I have noticed that going to bed late seems to have a negative effect even if I compensate in the morning by sleeping in.
For example, my dream recall tends to be pretty horrible if I go to bed ~4 AM and get up in the early afternoon, whereas I seem to remember dreams very well if I go to bed at 10 PM or something (which is obviously a much better time to go to sleep than 4 AM!).
The problem is that I share a university apartment with a good friend right now, and we both enjoy staying up for very long whenever we don’t have any important lessons earyl next morning, so time often passes during the night almost until sunrise. 
But maybe going to bed at around 1 AM or so will work well enough.