Cliches, those "old saws" that are used to make a point by applying them as similes and metaphors to people and situations in your writing, need to be avoided. Why? First of all, they make you appear less creative than you actually are. Let's face it: if you are a writer you are certainly creative enough to invent your own similes and metaphors and not rely on using the old worn-out ones.
Take a look at the examples below:
The two lovers did not see or hear one another on opposite sides of the sidewalk. They were
like two ships passing in the night.
Grace and Emily stuck together like two birds of a feather; neither was ever seen in circles
other than the ones they both shared.
Each of the above examples contains a cliche highlighted in boldface. Though they may not be familiar to you, they are old and have been worn out by the general public over the years. Beware: when you think you have created an original, it may well be one that has come and gone but is still familiar to enough readers to make you, as an author, appear non-creative. That makes it important to have several people of different ages read your work before you submit it for publication.
There are times, however, when using cliches may be permissible. For instance, look at the example below. It is dialogue, and it sounds as if it is coming from a character who is more than likely quite adept at using cliches.
"Why, I love eatin' jack rabbit. By damn, I'll gobble up a bowl uh jack rabbit stew, er even Welsh rabbit, in a New York minute if'n you'll cook it fer me!"
If cliches are appropriate for a character, you can get by with using them, even to the point of ridiculousness.