There’s a balance that all writers need to figure out: how much/what to read while they’re writing.
The Pros: really good writing should both inspire and teach. A great book should fill you up with ideas and thoughts on ways to play with your own writing. You should also be able to take away what works so well.
The Cons: It can get disheartening.
Here are the facts: if you want to be a writer, you have to read. A lot. And widely. And I think, if you’re passionate about being a writer, this shouldn’t be much of a problem. Chances are, you started because you love to read.
The balance comes into play regarding how much you read in your genre.
Yes, it is a good idea to read fantasy books if you write fantasy (or whatever genre applies). It is a good idea to be aware of fantastic books and popular books in your genre (which don’t always overlap). It’s just smart to be aware of what’s out there (and usually, you’re a fan of the genre you’re writing, so reading it isn’t exactly a burden).
But there can be too much of a good thing. As much as I love speculative fiction and YA, sometimes my brain needs to switch gears. It’s like, you wouldn’t go to the gym and only work out your arms for your whole life. Eventually you’ll have massive body-builder arms and toothpick legs. It doesn’t make sense, the same way it doesn’t make sense to pigeonhole your reading.
The trick is knowing when you’ve read too much of a good thing. When you’re about to jump off the deep end unless you set aside the book you’re reading and pick up a literary palate cleanser. When you need to stop reading all those fantasy books and catch up on literary fiction or romance or memoir. Because these books are not just a break from super-genre-focus, but can offer new and different approaches to writing to re-inspire you.