In the late 1990s, and early 2000s, every single American was well aware of the Monica Lewinsky scandal. She was featured in tabloids, TV specials, and especially rap songs. For quite a while, you could call any mistress a "Monica Lewinsky" and the reference would be very clear.

However, a child born in America today would have no concept of why Ms. Lewinsky is famous. And, in fifteen years, if that child stumbles upon a sentence in an early 2000s romance novel that refers to Monica Lewinsky, it's very likely that a Google search will have to provide the answer (or whatever search engine/method is being used in fifteen years)

Older books already provide us with the solution to understanding these outdated pop culture terms, in the form of footnotes. However, if you see an abundance of these "pop-culture footnotes" in a book, you have to wonder: could this author have imagined a world where people are reading his/her book 100, 200, or even more years in the future?

It should be without saying that, if you're including a plethora of pop culture in your literature, you shouldn't expect a long-term audience.

While few works with an abundance of pop culture references do survive, it is usually not because of the pop culture itself. Most classics are that way due to their ideas, significance, or quality. The fact of the matter is that, in ten years, the audience may not know what you're referring to, and will lose their interest.

Of course, this all depends on the medium of your writing. If you're writing an article, and only intend for it to be popular for a week, then sure---season it with as much pop culture as you like. But for most mediums: books, poetry, essays, etc---too many pop culture references will alienate your audience.

From a literary standpoint, pop culture references could be seen as "flash-in-the-pan allusions." An allusion is a reference, often indirect, to another body of work, history, event, place, or person. However, the majority of literary allusions come from well-established and lasting sources: history, mythology, and the Bible, for example. A much larger amount of people---past, present, and future---will be able to understand and relate to a phrase like "she had the artistic skill to rival DaVinci" as opposed to a phrase like "she had lips that were even plumper than Kylie's" But, who knows? Maybe Kylie will cement herself in the grand scheme of history.

What really keeps your work relevant, in my opinion, is appealing to universal things that people can relate to: family, love, emotion, injustice, and humor, to name a few. If you want to stay fresh, then write something people will actually want to preserve.