The importance of reading for writers
This post should take about 3 minutes to read through.
Stephen King says that "If you want to be a writer, you must do two things above all others: read a lot and write a lot." As an editor, when I'm editing a client's book, I can quickly tell whether the client is a reader or not. Another of King's quotes is that "If you don't have time to read, you don't have the time (or the tools) to write." There's no excuse for a writer that justifies not reading. (I highly recommend King's On Writing, it's an excellent book on writing.)
There are several important reasons that one must read. Even if you're a native speaker of the language in which you write, that doesn't mean that you can write that language well, nor does it mean you can speak it well. There are classes on rhetoric just like there are classes on writing. When reading, you learn how a language is structured, how good writing is supposed to feel. Besides the wealth of intellectual knowledge you get, which includes an expanded vocabulary, you also get an instinctual understanding of language that can't just be taught.
When a writer doesn't read, their writing is weak and awkward. It's instantly recognizable by any experienced editor or teacher, because the writer will make mistakes that not even amateur writers should be doing.
My own opinion is that an aspiring writer should read at least a hundred novels before they attempt to write one. I had read a hundred books by the time I was twenty, and I've read more than three hundred at thirty-four. I don't consider that number significantly high; I read for a few minutes every day before bed, and on vacations. Additionally, English is not my native language, so I had to read a lot to learn how to write adequately.
If you have difficulty reading, try audiobooks, and don't hear anyone who tells you that they're lesser in any way than written books. If you have attention span issues, reading is a good way to reclaim your attention span. Set aside the phone and read for ten minutes, twenty minutes, or more, without touching the attention-sucking rectangle of doom.
I would like to add two more rules to this; neither is my invention, I just don't remember where I read them.
Read books that aren't in the genre you write. This will help you expand your horizons, give you fresh ideas, and expose you to techniques that you might not be familiar with. You shouldn't read something you don't like, but if you write fantasy, try a bit of science fiction every now and then, some historical novels, possibly a classic or two. You may find that you like some of them more than you'd expect.
As for the second rule, I've read two variations: read good books and don't read bad books, because bad writing is contagious, and also, read a few bad books every now and then, because it helps you identify bad writing. I will try to unify both. It's good to know what a bad book is, because the thought "If this got published, why not mine?" has definitely jump-started more than one writing career (it did mine), but if you find that you're easily influenced by what you read—if for example you read one (1) space opera novel and decide you want to be a space opera novelist for the rest of your life—maybe avoid reading too many bad books.
So, in summary: read. It improves your life in countless, well documented ways, it makes you a better person, and it will make you a better writer. It gives you empathy, helps you understand other people, allows you to have amazing adventures, and teaches you things you would never know. As King puts it, "Books are a uniquely portable magic."