CASE 1: You're reading a book for fun, and find yourself totally engrossed. No matter what you do, you just can't put the book down. You don't want to do anything until you find out how the story ends. As a result, you don't let yourself sleep until you've finished the book, which you usually don't do until 2:00 AM - 3:00 AM.
PRACTICALITY - LOWCASE 2: You have to take notes on/will be tested on the contents of a book. Either through the accumulation of other work or through your own procrastination, you find yourself unable to begin your note-taking/reading until 10:00 PM - 12:00 PM. A massive LNRI ensues.
NECESSITY - NONE
CONSEQUENCES - NEXT-DAY EXCITEMENT ABOUT YOUR BOOK'S RESOLUTION
WORTH IT? - ALWAYS
PRACTICALITY - STILL PRETTY LOW, BUT HIGHER THAN CASE ONEI'm pretty sure these are the two primary (if not the only two) causes of LNRIs. Have I missed one? Let me know.
NECESSITY - HIGH
CONSEQUENCES - NEXT-DAY FATIGUE, POSSIBLE MASTERY OF BOOK'S MATERIAL (THOUGH USUALLY NOT)
WORTH IT? - USUALLY NOT