It's definitely not required. But I think death is commonly associated with good books because it represents a willingness to let the story go where it needs to go. We all have characters that we like (as readers and writers) and to let one of them die can be the hardest thing to do.
Some deaths are assumed, like the mentor figure, and some aren't, like a love interest or friend. But, if you're the writer and you're saving a character for no other reason than you don't want them to die, then I think you aren't letting the story go where it wants to go. However, if your story isn't calling for a character death, then injecting one in there isn't going to make it better.
As writers we convey the story, but we're not always directing it. One of the most difficult things to do can be letting that story take the wheel, no matter how heartbreaking it might be.