“If you’re fifty years old or younger,
give every book about fifty pages before you decide
to commit yourself to reading it,
or give it up.
If you’re over fifty,
which is when time gets even shorter,
subtract your age from 100—
the result is the number of pages you should read before deciding.”
~Nancy Pearl, Book Lust
Now, that's just a great rule right there. Freedom in literacy. There are too many good books out there to waste time on one you don't love. That's why I have abandoned a book I was 143 pages into; I was dreading my every opportunity to read. (And who on earth wants that?) So I set it aside. I may return another day, when all other books seem even less appealing. (Highly unlikely.) For now, I have replaced it with a brilliant read that I simply cannot put down. And that's just a better plan, in my book.
(No pun intended.)