For a casual look, rock a white and black horizontal striped crew-neck t-shirt with khaki chinos — these two items fit beautifully together. Want to tone it down with footwear? Introduce a pair of black and white high top sneakers to your outfit for the day. Keep this look ready to go when spring comes, and we guarantee you'll save time racking your brain for an outfit on more than one occasion. So as you can see, in your 30s you have a wide range of sartorial options.