A white crew-neck t-shirt looks so laid-back and cool when paired with khaki chinos. When not sure about what to wear when it comes to footwear, add a pair of dark brown suede boat shoes to the mix. As you can see here, this combination is a really wonderful option, especially for in-between weather, when the temperatures are starting to drop. This outfit should clear any doubts you had about dressing casually as a man in his 40s.