A grey crew-neck sweater and grey sweatpants are indispensable menswear essentials if you're piecing together an off-duty closet that matches up to the highest sartorial standards. Finishing off with black leather casual boots is an effortless way to bring a little zing to your ensemble. We highly recommend this one if you're on a mission for a winter-appropriate outfit that's as stylish as it is practical. All in all, a great example of casual fashion for men in their 20s.