Starting a new book is exciting. It’s like putting on a brand new pair of shoes on a sunny morning, with no puddles in sight. Sadly, the novelty wears off. Then, there’s that uncomfortable feeling at the prospect of leaving the book unfinished. The same book that starts as an exciting little activity becomes a nagging reminder that you failed to reach a goal.

Nobody likes starting a book and failing to finish it. So much so, I suspect, that it discourages us from starting a new one, in fear of not reaching the end. After all, who signs up for a marathon that they don’t expect to finish? Even if you ran an impressive 20 miles, you wouldn’t get the exhilaration of crossing the finish line and the satisfaction of officially achieving a commendable, well-defined goal that other people recognize and admire.

But is reading a book really about reading every single page that someone put between two covers? On principle, I think people would agree reading is about getting exposed to ideas that inform and influence the way we think. Surely, then, we can be done with a book regardless of whether we read it from beginning to end. And if we’ve “finished” the book in this way, shouldn’t we walk away satisfied and guilt-free?

Setting a goal number of books to read can foster the habit of reading regularly, a habit we all admire and covet. However, it’s easy to get carried away with trying to make measurable progress at the expense of approaching your actual goal. If you get fixated on officially finishing a book, you might be forgetting why you wanted to read it in the first place. By ditching a book when you feel you’ve had enough of it, you’re staying true to the real reason you set that goal of reading some special number of books by Christmas time.

In Super Thinking: The Big Book of Mental Models by Gabriel Weinberg and Lauren McCann, the authors tell a true story about a government that offered civilians bounty for killing rats in an effort to mitigate the local rat infestation. Specifically, they offered people money for each rat tail they brought in. They figured they could reliably track progress on the pest problem without having to handle the corpses. The plan backfired completely. Crafty entrepreneurs realized that they could capture a rat, cut off its tail, and then release it, so that it would live on to reproduce: more rats, more tails, more money. The pest problem worsened significantly.

But why all the gossip about rodents and dishonest bounty hunters? Well, Weinberg and McCann’s point is that metrics can be counterproductive. In the case of reading books, if you worry too much about how many books you’ve read front-to-back, you stray from your objective of learning and growing. Maybe you should change your metric or add a new one: the number of books checked out of the library, or the number of books you read for at least one hour. Anything that helps you make real progress and not counting rat tails.

Books aren’t perfect. Many of them are good. Many others are just okay. Sometimes, you benefit by leaving a book unfinished and moving on to another instead of persevering through to the end, regardless of how far you’ve made it. In that case, by quitting the book, you’re overriding a psychological flaw and making a more rational choice.

The sunk-cost fallacy, as defined in Thinking, Fast & Slow by Daniel Kahneman is:

We fall prey to this error when we stick stubbornly with a book just because of the time we’ve already sunk into it. If this book is no longer doing it for you, move on. There are millions of other books and many of them are better than this one. If you can cut your losses and push through the unpleasantness that comes with doing so, you’ve likely made the optimal choice.

If you feel guilty about not finishing a book you’re currently reading, you probably won’t start a new book. And so, if the book you’re reading loses your interest, you’ll end up losing steam and maybe reading no book at all. Unless it is important to you to finish this specific book, why not move on and keep your momentum going? By leaving a book unfinished and feeling good about it, you allow yourself to start a new book with excitement instead of guilt.

We’ve all finished reading a paragraph only to realize that we didn’t absorb much of the information at all. It can happen when we’re having trouble focusing, but it can also happen when you’ve lost interest. That’s okay. It might be time to move on. Life is long, you can come back to this book in some weeks, months, or even years if it’s a book you think is worth reading eventually. By moving on, you are valuing results above all else.

If you learn to ditch books with confidence, you’ll cover more variety of material. I think this is true not only because you start the next book sooner, but also because you avoid the reading slump you’ll inevitably hit when you’ve committed to a book that you have no interest in reading. By moving on to another book, you’re covering more ground when it isn’t worth staying put and drilling down for more.

You might benefit a lot from a book early on, but less so in later chapters. Perhaps you’ve effectively satisfied your curiosity, or maybe the book’s value is distributed unevenly across its sections. Regardless, you’re facing diminishing returns and the book might not be worth your time anymore. By ditching the book, you’re reacting intelligently to a waning profit.

If we choose to finish a book, let’s make that choice for a good reason, and not because leaving it unfinished feels like failure. Moreover, let’s relish the opportunity to make the smart, if counterintuitive, choice of bailing on a book when it isn’t worth the time. If we overcome the mental hurdles that stop us from ditching a book even when we are justified, we’ll be free to read more widely and engage more deeply.

I have some free time right now. Should I read or should I write? I’ve learned to choose by checking in with my body. Do I feel an appetite for absorbing new information? Or do I feel a need to express myself in some way? In other words, am I feeling

?

Classifying my mood on that simple criterion has helped me a lot. When I’m feeling productive, I know I’ll have a hard time quieting my mind to read. And when I’m feeling absorptive, I know it’s a great time to make progress on a book.

Recently it occurred to me I could add more binary tests like this one. After I determine I feel like consuming rather than producing, I might ask myself whether I feel like doing something active or something passive. Watching TV for example can be active or passive depending on whether you watch a documentary about an unfamiliar topic or rewatch your favorite sitcom.

By adding a second axis, we upgrade our binary test into a matrix. And the more criteria we add, the more precisely we can chart our moods.

Are you in a mood to expend energy or do you need to refuel? The same answer will have different implications for different people. For introverted people, having “expensive” capacity at a given moment offers an opportunity to socialize. For extroverted people, it might be a good chance to attend to personal chores.

After determining that you want to watch a movie – a fine choice when one is feeling passive-absorptive-regenerative, by the way – you can figure out whether you want to do your passive absorbing alone or with other people.

While going through this exercise, you don’t have to pick a point on each spectrum. I think it’s unlikely you’ll have answers for all. (Ah yes, I’m feeling productive-active-social-regenerative, that’s the word I was looking for!) But with every choice, you filter down many possible activities into the ones best suited to your current mood.

Are you in a social-regenerative mood? Meet with friends to do something that nourishes you. Or are you feeling social-expensive? Do something that you’re not easily motivated to do but that your loved ones want to do with you.

Choosing an activity based on how you’re feeling in the moment is a good way to evade the taxing experience of forcing yourself to do something through willpower alone. But learning how your moods and energy levels fluctuate is also useful for planning.

It’s important to notice which activities are expensive for you. Whether you’re a morning person or a night owl, dedicate your expensive mood to

. Make time afterwards for your regenerative activites. Whether you’re more introverted or extroverted, take note of how often you need social interaction to keep a healthy balance. If producing is important to you, dedicate time to absorbing as well. As Stephen King writes in his book On Writing: A Memoir of the Craft: