How much you pack depends partially on how long you stay. Generally, it's a good idea to travel light.  Expect you will need more room in your bags for your journey home to accommodate gifts, laundry and souvenirs. Should you need it, there are a reasonably priced one-day laundry services in all large cities. When traveling in the winter, do bring a winter jacket, rain gear and sweater. An umbrella is also recommended.