Once someone or a couple are in a house, there [ADDED: often] really isn't a big problem although I imagine some people might want to make changes to their house or even upgrade to the degree their situation changes long-term. The real problem I see (and that has numerous people I know moving) is that they had a relatively small (often expensive) city apartment that was mostly for relaxing in the evening and sleeping and now it's a 24-hour thing.