Consider pairing a charcoal wool waistcoat with charcoal dress pants for a proper refined look. As for the shoes, you can go down the casual route with dark brown suede brogue boots. As a 30-something Millennial guy, you want to start dressing in a classier manner. In this case, combos like this are ideal as inspiration.
Dark Brown Suede Brogue Boots with Charcoal Wool Waistcoat Outfits In Their 30s
Go for something classy and timeless in a charcoal wool waistcoat and a charcoal suit. For a more laid-back twist, why not introduce a pair of dark brown suede brogue boots to the equation? In your 30s, you probably want to start dressing more maturely. In this case, looks like this come in very handy.