meaning - How much time must elapse for an item such as a book to become classic?

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"?