Let’s consider, for a moment, the concept of the fall “go-to.” The drink you reach for on a brisk evening: whisky. Your preferred Sunday afternoon viewing: football. Your fabric of choice for warmth: flannel. Autumn is all about trusting your instincts—and when it comes to comfort, you can do a lot worse than flannel.

Why it wears so well
The word flannel comes from a strange-looking Welsh word, gwlanen, which means “wool.” The warmth of the cloth depends on the napped surface, where air pockets are trapped between interlocking fibers. It’s the nap that makes flannel so user-friendly. The more nap you have, the happier you are.

What you need
We’re only talking suits and trousers here. The checked flannel shirt, good for everything from sitting in front of the fire at the fishing lodge to stage diving at a metal show, is something everyone is familiar with.
For cold-weather suits, there is no better fabric than a light flannel. Single- or double-breasted, and even with a vest. We recommend a two-button single-breasted suit if you’re going to own only one. For colors, lighter greys are less stuffy, while darker greys are more formal. Navy is also a good choice. For more attitude, go with a pinstriped flannel.

Grey flannel pants should also be a staple in your winter wardrobe because of their incredible versatility. Wear them to work with a dress shirt, V-neck sweater and tie. Then, on the weekend, pair them with a cable-knit sweater and chukka boots. And while grey has always been associated with flannel, you can find other colors as well, including navy, brown and beige.

What you want to avoid
The title of the novel The Man in the Gray Flannel Suit wasn’t chosen at random. Dealing with issues of conformity in the workplace during the 1950s, the standard uniform of the American worker was grey flannel. Without adding a striking shirt and tie combination, you do run the danger of being swallowed in a sea of grey. So if you opt for a grey suit, be sure to add a bold touch. And don’t shy away from a pocket square, either.

Treat it right
To keep your flannel performing its best, you need to know a couple things. Steaming or hanging it in the bathroom while you shower will help it regain its shape after being worn repeatedly. When hanging the pants, never slot them through the bar on your suit hanger or you may end up with a permanent crease across them. And if you spill something on your suit, always blot, never rub (you’ll risk having a weird, fuzzy-looking spot on your suit).

What it all means
Once you wear a flannel suit or flannel trousers and discover how incredibly warm and comfortable they are, you’ll begin to wish winter would never end. And that’s the magic of “go-to” things like flannel suits. They excel under the right circumstances—and they’re indispensable to your wardrobe.