Pairing a grey denim jacket with jeans is an awesome pick for a casual ensemble. Why not take a dressier approach with shoes and add a pair of charcoal suede chelsea boots to the mix? If you want people to see maturity in you, a look like this is what you're looking for.
Grey Denim Jacket with Jeans Smart Casual Warm Weather Outfits For Men In Their 30s
For something more on the relaxed end, pair a grey denim jacket with jeans. If you feel like dialing it up, complete your look with black leather casual boots. As you mature into your 30s, you probably want to start dressing like a grown man. If that's the case, ensembles like this are perfect as inspiration.