This casual combo of a dark brown crew-neck t-shirt and khaki vertical striped chinos is extremely easy to put together in next to no time, helping you look dapper and prepared for anything without spending a ton of time rummaging through your closet. With footwear, go for something on the laid-back end of the spectrum by finishing with a pair of high top sneakers. This pairing suggests how to keep killing in the casual fashion department as a 40-year-old.