I can only read one book at a time.
When I start a book, I have to get to at least 40 pages before putting it down. Stopping anywhere between 40-49 is okay. Anything below 40 is impossible for me to do. If I keep reading past the 40s, I have to go another thirty pages to 70. Stopping between pages 70-79 is great. After that, it has to be 100 or higher. Can't stop on, say, page 81. Just can't. Can't stop on a page that has a 3 in it, and I can't stop after reading 13 complete chapters. I'll keep pushing until I've read 14 chapters.
I can't dog-ear my pages.
I can't get anything on my pages. If I accidentally stain a page in a book, I'll buy another copy.
If the spine breaks (especially on a new hardcover), I can't keep reading it. I have to buy a new copy.
I have three bookmarks I use. I have one for hardcovers, two for soft covers. Never anything different.