For a casual look, consider pairing a navy denim shirt with jeans — these pieces fit really well together. A no-brainer outfit appropriate for 30-something Millennial guys.
Navy Denim Shirt with Jeans Chill Weather Outfits For Men In Their 30s
If you prefer casual street style style, why not take this combo of a navy denim shirt and jeans for a walk? Take this ensemble a more sophisticated path with a pair of black leather desert boots. This outfit shows that reaching age 30 is no reason to shed casual style altogether.