Definitely an adapter! Then in the case goes my camera, clothes, shoes and passports and the tickets! I normally put in a sandwhich or two as I get low blood sugar and can’t afford to be caught out hungry. I put as least as possible in my case because I want the weight for all the goodies and souveniers I like to bring back with me.
I like to keep things minimal. I would only bring a few pairs of clothes enough for the duration of my stay and a few extras. I would bring my phone and my laptop. I will also bring a power adapter because it helped me to bring those when traveling to another country that doesn’t have the same power socket.
I always pack too much. I love having a good choice of what to wear and so I’m prepared to pay to put a suitcase in the hold. This annoys my boyfriend who likes to travel with carry-on luggage only. However, he invariably manages to sneak soething into my big case.