When we talk about "the essential" in a fashion-ish (I have totally invented that word) way, it is possible to include the mention of hats, boyfriend jeans and camel coats. We're talking about "the essential", not a simply essential, just that determined kind of things that people and fashion industry have accorded to wear/use during that determined time of the year.
But that doesn't mean that "the essential" is a term we can only use when talking about fashion. The same way, a journalist needs to grab a little notebook and a pen every time he goes out of his house; and a for a photographer, the most important thing to have with him is, of course, his camera. So that would be "the essential" for them.
"The essential" is different for everyone and it can change. On a rainy day "the essential" would be lying on the bed while reading a book, or maybe someone prefers studying (I'm sure not that much), or drinking tea. There's as "essentials" as people in the world, or even more. So, what is your essential on a Fall day? Let me show you mine.