This combo of a navy fair isle crew-neck sweater and light blue jeans is simple, dapper and super easy to copy. And if you wish to easily smarten up this ensemble with one single piece, why not add a pair of brown leather casual boots to your outfit? So so as you can see, it's a neat, not to mention spring-appropriate, getup to have in your transeasonal rotation. This combo illustrates how to keep killing in the casual style department as a gentleman in his thirties.