When the setting allows a laid-back outfit, you can rock a navy short sleeve shirt and blue jeans. Introduce a pair of dark brown chunky leather derby shoes to the equation to completely change up the ensemble. A fail-safe option for mature men who are on the lookout for age-appropriate outfits.
If it's comfort and functionality that you're looking for in menswear, wear a navy short sleeve shirt with blue jeans. And if you need to easily kick up your outfit with one single item, complete your look with dark brown chunky leather derby shoes. This is a modern yet age-appropriate pairing for a 40-year-old guy.
For a foolproof casual option, you can't go wrong with this combo of a navy short sleeve shirt and blue jeans. To introduce a bit of flair to this ensemble, complement this ensemble with brown suede brogue boots. Rest assured this ensemble is something you can totally wear as a mature gent.