This is the first item every guy should buy when building out his wardrobe

When a man finally reaches adulthood, at some point he looks at his wardrobe and finds it lacking.

At that point, he must make a choice: what should he buy to fill those holes in his closet first?

According to Italian menswear designer Brunello Cucinelli, who recently spoke with GQ, the answer to that is simple: a beautiful, versatile blazer.

We at Business Insider have extolled the virtues of the blazer before, but Cucinelli's point is even more specific.

"A beautiful blazer is the starting point," he told GQ. "You can wear it to work, to get a newspaper, to dinner, a T-shirt underneath, or a proper shirt with a tie, or anything."

The versatility is what makes it so beautiful - and useful. It's an investment that will pay dividends in the coming years, and if your closet is missing it, you have so many fewer options for wearing the other items in your closet, too.

Here's what to keep in mind when you buy one:

• Color: Our advice has always been to get one in navy, as such a go-anywhere-do-anything color just increases the versatility of the garment.
• Model: Structured versus unstructured is the question all guys ask when buying their first blazer. Structured is more formal, like a suit jacket, while unstructured is less formal and more like a regular coat. In fact, this question is not one that can be answered universally - it's different for every guy. You must consider where you'll primarily be wearing your blazer, and then decide which kind will better fit into your lifestyle.
• Brand: Some of our favorites include models by J. Crew and Suitsupply, but we're sure your favorite brand makes a great one as well.

Don't be put off by the high price tags you might come across for the piece - we can assure you, it's more than worth it.