I never finish everything I start and I’ve actually got the opposite as a goal, kind of – to never spend more than 50 pages on a book I don’t enjoy. Life’s too short to read crappy books. But it sounds like you were enjoying those books and just got away from them for too long, which is a different issue.
I think another goal of mine is to never read more than two books at a time, one fiction and one non-fiction (graphic novels/comics living in their own category). Sometimes I feel like I’m George in Aspects of Love. I hope Will never gets mad and rearranges my bookmarks.