This combo of a navy sweatshirt and mint chinos makes for the ultimate off-duty style for any man. You can get a little creative in the footwear department and introduce athletic shoes to this look. Off-duty getups for mature gentlemen aren't actually that hard, as you can see.
If it's comfort and practicality that you appreciate in a look, consider pairing a navy sweatshirt with navy jeans. Complement this look with a pair of athletic shoes to keep the ensemble fresh. This combo should erase any doubts you had about dressing casually as a gent over 40.