Question: Mentioning a book to an individual to include in their list as *classic* was met with...

> 
> I wouldn't call "Book Name" a classic - it's less than 11 years
>  old.
> 
> 
> 

This got me thinking about when a book or other item (car, slang, recipe, etc...) becomes a *classic*. In my initial investigation I stumbled upon this description...

> 
> A novel can be called a classic when there is a significant time
>  period between its publishing and the current age we are in. In other
>  words, it has to be old, as well as critically renowned as a good
>  novel. Then, it can be called a classic.
> 
> 
> 

While the above may help define what constitutes a classic, it doesn't define the amount of time that needs to pass before that criteria is met.

Does the designation *classic* truly imply that a significant amount of time has passed since the work's creation, and if so, how long must that period be to qualify as "significant"?

Answer: 
Time, as they say in contracts, is not of the essence. For the OED, a classic is:

> 
> A work of literature, music, or art of acknowledged quality and
>  enduring significance or popularity. In extended use: something which
>  is memorable and an outstanding example of its kind.
> 
> 
> 

The entry is silent on how long it must endure to be of ***enduring*** significance or popularity.
There is no definite length of time which must pass before something becomes a classic. The requirement is that sufficient time has passed during which it becomes famous because of its quality.