Consider pairing a long sleeve t-shirt with black jeans to achieve new levels in your casual fashion game. If you wish to easily up the style ante of this outfit with one single item, introduce black chelsea boots to the mix. As you can see here, it's super easy to look awesome and stay cozy when chillier weather comes, all thanks to ensembles like this. This outfit should clear any doubts you had about wearing casual clothes as a mature gentleman.