Marrying a grey plaid blazer with white dress pants is an on-point option for a smart and refined look. Avoid looking overdressed by finishing off with a pair of beige suede low top sneakers. When spring is in full effect, you'll appreciate how great this ensemble is for weird transition weather. As a 30-year-old guy, you want to start dressing maturely. If that's the case, combos like this are ideal as inspo.