The military look and variations thereof come and go every few seasons. The same jacket that might be "safari" one spring could easily be reinterpreted as "military" in the fall. The sharp tailoring and shiny brass buttons are a little more obvious and definitely wax and wane as far as popularity goes, but tailored pieces are very flattering to many people, so a more understated style could work well for years. As with any trend, the far edges of it will be "out" relatively soon, but more moderate items will work for a long while.