Now...a little more on the induction skill known as the Re-Reading State Test.
Don't know what is the Re-Reading State Test (RST) yet? Well, you should! When done right and incorporated into your repertoire of induction tools, it is the one reality test that can help you get lucid more reliably than other means of testing whether you are awake or dreaming. If you don't know what it is yet, catch up on your reading about it in this previous post: To Lucid Dream Test Your State By Re-Reading
Re-Reading State Test: Challenge Question
Here is a tricky question that should challenge even the most advanced oneironauts. The RST is a daytime skill practice. It can be practiced whenever you remember to check in with your state of consciousness, when the thought occurs to you that you might be dreaming, or when you encounter dream-like phenomena in the waking state. But you don't necessarily set the intention to practice the RST in the dream state. Why not?
Why would you only intend to conduct an RST while awake, but not necessarily while dreaming?
Let's start with the context when you are practicing the RST while awake: If you truly are awake--there should be no true indications that you are dreaming—aka there are no "dreamsigns." Yet, you hold similar logic in the nonlucid dream state that prevents you from becoming lucid. Therefore, conducting a state test as reliable as the RST to confirm that you are awake is rather helpful here.
In short, the RST improves your accessibility to remembering how to challenge the deeply rooted assumptions that you are awake, and your rationale for 'How do I know I am not dreaming?'
Contrary to what most people say, the way the RST actually works has little to do with just creating a "habit that carries over into the dream state". While there may be some conditioning that takes place, LaBerge and company emphasize this has more to do with increasing accessibility to memory.
Accessibility and availability are psychological terms regarding memory retrieval. For a memory to be accessible, it has to be available in the first place—meaning you first must have a solid understanding of the concept of "How do I know I am not dreaming right now?"
Now let's look at the context in which you would perform an RST while dreaming.
Since you truly are dreaming, there should be indications that you are dreaming—because dreams are fraught with dreamsigns. If you're already considering that you're dreaming, essentially, there's no need to elicit another dreamsign by reality testing because ideally you would've already recognized one of the many dreamsigns around you. In fact, conducting a state test at this point can actually undermine your lucidity. Here, it is better to focus on recognizing the dreamsigns that are already present and trusting your lucidity, as opposed to conducting a state test that has a chance of producing a false negative.
Admittedly, it is still possible to overlook dreamsigns and the RST can be a useful back-up tool for becoming lucid in such cases. Still, it may help to tweak how you focus your mind’s intentions in a way that could be more productive—namely, by focusing more on dreamsign awareness, and letting go of the notion that you have to reality test in dreams to get lucid. Understanding these concepts more thoroughly will help you evolve as a lucid dreamer.
These concepts get easier and easier the more you are exposed to them and put them into practice—just like learning any skill.