We say a resounding yes to this casual pairing of a white and red crew-neck t-shirt and jeans! And if you wish to instantly dress down this look with a pair of shoes, why not throw in a pair of tan leather work boots? During the winter months, when warmth is top priority, it can be easy to surrender to a less-than-stylish outfit. But this outfit is a stark illustration that you can actually stay cozy and remain equally stylish in the winter months. Wondering how to nail casual outfits as you turn 30? This combination is a vivid example.