This combination of a trenchcoat and a black and white crew-neck t-shirt strikes an interesting balance between dressy and laid-back. For maximum style, add a pair of black suede tassel loafers to your look. This combination is probably what you've been looking for as a gentleman in his thirties.
A trenchcoat and a black and white crew-neck t-shirt are the kind of a fail-safe outfit that you need when you have no extra time to put together an ensemble. Parade your sophisticated side by finishing with a pair of black leather chelsea boots. Combos like this go a long way towards maturing your style as a 30-year-old gentleman.