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.
After I got married, we moved from my decent size house (3000 square feet) to a 1700 square foot apartment so we - my wife and two step children - could be in a better school system. I insisted on finding an apartment with a separate office. The office was small - built in desk and just enough room for chair, but I knew I would more than likely be working from home occasionally. We probably could have gotten some place a little cheaper if I didn’t insist on closed in office.