You can look casually cool without really trying by opting for a blue crew-neck sweater and chinos. Beige plimsolls are a surefire footwear option here that's full of character. Men who wonder how to pull off modern off-duty outfits as you pass the big 3-0, you have your answer.
Try teaming a navy blazer with chinos and you'll be the epitome of masculine sophistication. Feeling venturesome? Shake things up by finishing off with beige plimsolls. This combo should clear any doubts you had about wearing casual clothes as a gent in his thirties.