We like to throw the phrase “cliche” around here on site, but I think sometimes many do not know what it means, occasionally targeting legitimate narrative techniques as cliches.
A TROPE is a utilitarian and artistic tool for writers. They are forms of expression, syntax, idea and metaphor that bind a story together. Whether its describing a dynamic between two characters or a very specific event with outcomes.
The more a trope is used, the more it becomes ‘cliche-like’. A CLICHE is a trope thats indicative of the genre its being used in, a formulaic trope. At its worst, it means something is so unoriginal and formulaic it fails to retain the original meaning or impact, to the point of tedium.
For example, a common trope of the zombie genre may be characters who are bit and try to hide the wound (“Infectee”...trope). Is it cliche? Perhaps, depending on how often you see it in the genre. What definitely is cliche is for example, a zombie story where the zombies actively say “braaaaaaains”. At least when zombies were becoming more mainstream this was definitely the case. Time and culture can also affect how severe a cliche is.
While a majority of any given idea have already been done to death (regardless of whether we've discovered these ideas), there are an infinite number of ways one can combine tropes into a totally unique experience.
I highly recommend using the site http://www.Tvtropes.org. Its an incredibly useful site detailing a variety of tropes and analyzing how they are used. They can be implemented into your stories to help bring cohesion, authenticity and believability to a story.
Additionally, people might say “well whats the harm in being cliched”, and I might answer “quite a few things”. Human brains are hard wired to need stimulus; when you experience the same thing over and over again you don’t get that experience necessary to grow as a person. You stagnate and become dull. Complacent.
I imagine thats why those immortals we read of tend to off themselves after an inordinate amount of time: you can only read books and watch every movie in existence so many times before going insane with boredom. Not to mention, there is a level of achievement with taking risks and going where no man has gone before. Whether it was worth it or not, we will never know until we make that first step.
ps. My favorite cliche from this site by far, are certain entity descriptions.
"It had an impossibly wide smile, with too many teeth"
"it was too tall and skinny to be a human, with pale skin"
"They were wearing a black hoody"
Alright, I'll stop. You get the point.