This pairing of a turtleneck and a crew-neck t-shirt is undeniable proof that a safe casual outfit can still look really interesting. Not sure how to finish off? Introduce a pair of black leather sandals to the equation to change things up a bit. Totally summer-ready, you can rock a version of this getup throughout the summer. Gents who wonder how to wear modern off-duty looks in your thirties, you have your answer.