If you're a fan of off-duty combinations, then you'll appreciate this combination of a navy crew-neck t-shirt and navy jeans. Tap into some David Gandy dapperness and spruce up your getup with brown suede desert boots. This outfit is a viable option when it comes to crafting a standout outfit for unpredictable fall weather. All in all, a perfect demonstration of casual style for gentlemen in their 40s.