This off-duty combo of a denim jacket and grey jeans is a solid bet when you need to look casually stylish but have no time. Let your sartorial expertise really shine by finishing off your look with black low top sneakers. So as you can see here, it's a seriously stylish, not to mention spring-ready, combination to have in your transitional sartorial collection. Wondering how to nail casual outfits in your 30s? This combination is the perfect answer.