Strunk and White wrote in The Elements of the Style to "omit needless words." What makes a word needless, and when is it OK to be redundant?
A few weeks ago, I was talking with some reporters from a local radio station, and they said they had been debating whether it would be redundant to say that the unemployment rate “remains unchanged at five percent.” Remains and unchanged convey the same idea. You could say, “The unemployment rate remains at five percent,” or “The unemployment rate is unchanged at five percent,” and they both mean the same thing, but the reporters had decided it was OK to use both words because together remains and unchanged added emphasis, which is especially important in an audio program where people may miss a word or two, and I agree. It may be technically redundant, but it doesn’t bother me at all.
Social graces also play an often overlooked role in word choice and can be a justifiable reason to include unnecessary words. You didn’t get the job is sufficient to convey your meaning, but adding a “needless” lead-in helps soften the blow: I’m just writing to let you know that you didn’t get the job. Yes, it includes “unnecessary” words, but it sounds nicer.
In some cases, words are technically redundant, but serve a clarifying purpose.
For example, chai means “tea” in Hindi; therefore, chai tea technically means “tea tea.” In America, however, the word tea calls to mind simple black tea. In our culture, chai is a special kind of tea, and the word chai on the menu adds specificity. When chai was first introduced in America, customers probably wouldn’t have known that it was tea if they just saw the word chai on the menu, so writing chai tea was a wise business choice. Today, now that most people are familiar with chai, you can make more of an argument that the word tea is redundant or unnecessary.
Similarly, cider is technically juice pressed from apples, meaning that apple cider is redundant, but given that we can now buy blueberry cider, peach cider, and so on, apple cider makes it more clear what is in the bottle.