This combo of a grey denim jacket and charcoal chinos is on the off-duty side but guarantees that you look on-trend and incredibly sharp. Add a modern twist to an otherwise mostly dressed-up look by sporting low top sneakers. Seeing as it is getting chillier every day, this outfit is a wonderful idea for the time in between seasons. And if we're talking casual outfit ideas for guys in their 30s, this getup looks nice on almost anyone.