Some of the progression is very subtle, but I have found noticeable differences in each stage. For example, I see myself around Stage 6 since major distractions have ceased and I am working on dullness - this has lead to a much deeper meditation practice and I didn't fully realize dullness was a challenge until I followed this guide. Granted, the practice can be dry sometimes, so I like to sprinkle in guided meditations from the "Waking Up" app or "Insight Timer". I also HIGHLY recommend Yoga Nidra practice for those who have a difficult time falling asleep.