Reading Levels
Often as a reader, when being approached by a non-reader (however one might define a non-reader, or novice), I am forced to think about reading in levels, and give it a type of hierarchy. One expects a reader of a certain level to find it "easy" to read material on their own level and below, while "difficult" or "draining" to read above.
It is tough to give such a ranking to various types of material, but easier to put forth an opinion on the same (and fun). One obvious thing to exclude is material meant for kids: I am only considering adults here. (As mentioned above, this ranking is entirely based on my opinion)
Coming up with titles for said ranking is tough (very subjective), nonetheless I shall give levels of reading material as:
Self-help
I didn't dwell on this level much, but I did start by reading some famous ones like Think and grow rich, Rich Dad Poor Dad, The man who sold his ferrari. Books meant more for the general audience and, of course, self-help. A person who claims to be a reader but has only read up-to this level should stop doing so.
Commercial
This level is mostly about novels and magazines, so more focused on entertainment. There are certain sub-levels, but overall this material here has easier language and provides the reader motivation to read further, hence is easier to get through as well. Some novels are mainstream (Harry Potter, A song of ice and fire, 1984) and easy, while others are harder to get through (Lord of the Rings, Sherlock Holmes and even Pride and Predujice. These aren't harder per say, but have an older language, same as any works of Shakespeare). Overall to be at this level is to be a consistent reader, and being passionate about reading novels. (Also I think I should mention the Discworld series here as well, just for the sake of it)
Introductions
Here we leave the realm of fiction and enter reality. Books here are generally considered for obtaining useful and often interesting information on various topics/concepts/fields . Books that I have read on this level are Guns, Germs and Steel, Sapiens, Poor Economics, Freakonomics, Deep Work and many more. These seem like a good introduction to a certain field when read for the first time, while being easy to read as well, though one has to be determined enough to get through it all.
Specializations
As the name suggests already, here we have entered the realm of academics. Most frequently read by graduate (pre/post) students and above, material here is generally not touched by the normal populace. Though a majority of students do read such material, it is only when one does it consistently and with enough passion that they can be considered a reader at this level. Ounce a person reaches here, they would hardly ever go back to the ones above. (Even if they do, it'll not be below the Introductory ones). Being a reader at this level is not about reading books/papers in a field as an assignment or in order to gain a degree, but reading them just for the sake of obtaining that knowledge.
Expert
One would usually find authors here, people who research and write often. They are either novelists, researchers or in some cases just passionate readers/writers. Years need to be spend in the level above in order to get to this level of reading. By this time one has read so much, one feels compelled to pour out all the words out into the world. (Not all authors are extremely into reading of course, but I think every "expert" level reader would eventually want to pen down their thoughts). I would love to be at this level someday.
This list is not meant to be accurate or rigorous, but somehow roughly maps my own reading levels through the years. I have put a list of everything I have read here, if anyone is interested.