It's something people say all the time: Don't ask a yes-or-no question in a tarot reading. Just about any introductory tarot book you pick up, or any reader you ask for advice, will deliver this counsel sooner or later. There seems to be a broad consensus that tarot is just not good for yes-or-no questions, that it can't (or won't) answer them, and we should never bother to ask them. But most people don't talk about why that's the case.
Tarot is a narrative medium. Whatever question you ask, you get an answer in the form of pictures, symbols, and abstract themes. A tarot reading tells a story with its own characters, conflicts, and even a progression from the past through the future. This means that in order to get the most out of tarot, you want to ask questions that can properly be answered with this kind of story.
In divination, it's tempting to ask small, narratively closed questions—things like, "Will I get the job?" or, "Is he going to call?" After all, we come to divination because we want answers about our lives; more often than not, we'd prefer a straightforward yes or no over something more complicated. However, these questions don't give tarot room to do what it does best. They don't lend themselves to the narrative expression that characterizes tarot as a divinatory medium. Asking tarot a yes-or-no question is like asking Michelangelo to draw a stick figure; sure, he can do it, but he'd much rather be painting the Sistine Chapel.
The best questions for tarot are the ones that give your reading room to breathe. These are, generally speaking, open-ended questions: who, what, where, when, why, and how. Questions like these can't be answered in a single word. They require elaboration and context. To know, "Is X going to happen?" you really only need a yes or a no. To know, "Why is X happening?" on the other hand, you need a much fuller picture. You need to know who the people involved in the situation are, what drives them, and what effect their actions have on you. You need to think about what's happened in the past, the relationship between the past and the present, and the way that current events will continue to shape the future. In short, you need to tell a story.
This is the kind of question with which tarot excels. Tarot is adapted to answer open-ended questions that encourage you to take a step back and consider the whole of your situation. Even if you sometimes just want an answer to a smaller question like, "Will I get the job?" you'll find that your tarot readings provide narrative context anyway. If you ask, "Will I get the job?" and you pull the Six of Swords and the Eight of Wands, that tells you not only that you'll get hired, but that you'll hear back very soon and the whole hiring process will move very quickly. If you ask, "Will he call?" and you pull the Three of Swords and the Queen of Cups, that tells you not only that he won't call, but that he's more interested in someone else. Tarot always tells a story.
Does this mean you must never ask a yes-or-no question in a tarot reading? No, not necessarily. You can ask tarot anything you want to know. However, if you ask a small question without room for storytelling, you may find that interpreting your cards gets a lot harder. Imagine asking, "Will it rain on my vacation?" and drawing the Three of Pentacles. Is that a yes or a no? The answer is ambiguous. The themes associated with this card are teamwork, creativity, and mastery, but it's not obvious how any of those things relate to a question about the weather. You could plausibly look to the specific imagery in your card to see if the weather is depicted as fair or foul, but it feels like thematically, the card is trying to express something that just can't come through.
Now think about the card, not as answering, "Will it rain?" but as answering, "How will the weather affect my vacation?" Here, the themes of the card leap out: You'll find yourself around other people. The weather won't isolate you or keep you stuck at home; rather, it will push you toward other people and encourage you to find a dynamic social setting. Chances are good, then, that the sun will be shining and you'll be able to get out and about.
In a way, the card still answered the closed yes-or-no question, but it did so by telling a story. That is to say, the best way to answer the smaller question was to take a step back and answer a bigger question first. This is how tarot shines. Even if we only want a yes-or-no answer, we often get that answer by asking a narrative question and using tarot to tell a complete story. We get better, more satisfying answers by letting tarot do what it does best. The way to get the most out of your tarot deck is to let it tell you a story in every reading, rather than trying to confine it to a strict yes or no. If the yes or no is what you really want, you'll find that the story leads you there eventually, and does so in a more satisfying way than if you try to take a shortcut and avoid the story altogether.
The advice to avoid yes-or-no questions in a tarot reading is solid, but it doesn't mean that we can never ask those questions or that tarot will break if we try to use it for something specific and concrete. Instead, it means that even if we're looking for a yes-or-no answer, we'd do well to keep ourselves open to other information, and to look for the ways the cards supplement a simple "yes" with information about who, what, where, when, why, and how. What we really mean when we say, "Don't ask yes-or-no questions" is, "Don't only ask yes-or-no questions." Don't look for the yes or no to the exclusion of everything else your reading might be telling you. That extra information tells a valuable story, and you'll understand your situation better for having listened to it.