I don't consider myself a 'great' reader, but I'm aware my count probably argues otherwise...
I read a mix of fiction and nonfiction, short and long, YA and adult. I also read every day and am a fairly fast reader. Easy/YA/rereads I can read 100-200 pages in a day. More adult work or nonfiction, more like 50 pages. I also usually have 2-4 books going at once, so I always have something to pick up no matter what mood I'm in. Some days I'm not up for dense nonfiction or really philosophical fiction, so I have something easy to read instead.
Different books, I remember different amounts. For fiction, whether easy or hard, I tend to remember the characters, the plot in broad strokes, and how the book made me feel/how much I liked it. I'm not great at remembering details, but that's always been true no matter how many books I read in a year.
Non-fiction, it depends why I was reading it. Reading history/biography, I'm usually not trying to deeply learn the topic, but bits and pieces stick in my memory. Self-help type books, if they're good I'm trying to come away with 3-4 big picture ideas. If they're not applicable to me, I don't worry about remembering much. Philosophy/spirituality books I'm looking for thoughts that resonate, and letting the rest slide by. Science I try to read more carefully, but I also read much less because it's hard to find good ones that aren't too pop-science. Sometimes I take notes, if it's a book I particularly want to remember (usually good self-help, spirituality, and science).
Looking back at my list for last year, I remember at least a vague arc and an emotional impression from all the fiction. The only ones that really run together are the mediocre self-help books, which I read mostly for entertainment.
Questions for all the great readers:
1. are most of your books short/easy reads? Or are you spending hours per day reading? Or are you exceptionally fast readers?
2. When reading easy non-fiction, when you look back at your list of books later, do you remember anything about the plot?
ETA: Forgot to mention I don't do audiobooks, everything is physical except for a few e-books that I couldn't get from my library in hard copy.