The changing seasons and falling leaves can make us feel contemplative, as we begin to ponder life's great questions.

"Is it a shirt or is it a jacket?" is not one of those questions.

But the beguiling overshirt, shirt jacket or shacket, if you're into portmanteaus, is everywhere right now. And rightly so because it's a reliable go-to for staying just the right amount of warm throughout fall and winter.   

These are 10 shirt jackets for your consideration. Wear them, layer them, love them.

The Blanket Flannel Field Jacket combines vintage military style — hello mitered patch pockets — with heavyweight double-brushed flannel. Buck Mason, $158

Here's a quilted wax canvas shirt jacket that will never go out of style. It's tough, versatile and ready for anything. Huckberry, $288

This hardworking shirt is reversible, made with ripstop cotton on one side and smooth nylon on the other, and it's insulated so you can stay warm on the coldest days. Topo Designs, $109

Not all plaid shirts are created equal. For instance, this oversize plaid shirt jacket is based on a vintage model from the 1960s and made from heavyweight wool twill cloth with a yarn-dyed pattern and enameled snaps at the chest pockets. RRL, $445

Here's a handsome tweed option that's inspired by suit fabrics but insulated with recycled poly fill for added warmth. Throw in some fine detailing, like a leather locker loop and antique brass snaps, and you'll look better than you have to. Billy Reid, $448

This rugged Maritime Shirt Jacket is inspired by New England fishing communities. The 13-ounce, 100% organic cotton is given a rich moleskin finish with a soft yet sturdy feel that's equally suitable for chilly days on the boat as it is lazy weekends on the couch. Taylor Stitch, $188

Throw on a Blanket Shirt, and you just know you're going to be cozier than the next guy. The best part: You can choose from dozens of different styles. Outerknown, $168

Pendleton has been making ruggedly comfortable shirts and blankets or a long time. This is no exception. Extra-soft cotton chamois is woven with a classic striped pattern, button chest pockets, and an oversize fit that's perfect for layering. Stag Provisions, $199

Faherty's Legend Sweater Shirt is available in more than 20 patterns, including a variety of solids, checks and plaids. So you're only limited by your imagination. And by what's in stock. Faherty, $178

This heavyweight twill shacket lives up to the name, working great as a shirt or a light jacket, and it's sleek enough to fit under a bigger coat when needed. Everlane, $74