Right, it depends on which two places you're moving between. Your device probably won't work well in North America, for instance, or in Japan. (In NA, it might be workable if the device doesn't care about line frequency since it's 60Hz there. In Japan, it'll work if 200V is close enough, but that's a significant difference from 230V. And the line frequency is only the same if you're in Tokyo or east of it.)