This is a bit off-topic maybe but the answers given by many make me curious:
Why 2-3 years between company transfers? It was (is?) about the same when I was growing up and my father was active-duty in the Marine Corps... 2-3 yrs in any one place unless someone applies for an extension.
Meanwhile, for me, hopefully I can make it past that 2-3 year mark, after growing up that way I know I tend to get "itchy feet" around about then and start looking for a new place to live (even if I can not transfer or switch jobs) or somehow wind up hanging with a different group of friends.
Hubby and I agreed that we'll give it about 5yrs here and then analyze where we are (financially, career stability, as well as happy where we live) and if it's all good, we'll probably stay, otherwise considering moving to the US.
You answer your own question. People get older, have families, grow roots. Those sent around the world on assignments tend not to be middle aged. Nobody would put up with it for long.
When we moved here, we knew that the international contract had a maximum life of 5 years. My husband was contracted for 3 years, I was able to find a local job before we moved (extremely rare).
After 5 years we decided to localize and are coming up on 9 years with no plans to move, especially since we bought our apartment.
As long as we continue to enjoy our home, area, and jobs, we'll stay, assuming the IRS issues don't make it impossible. (We report and file, so hopefully that'll continue to just be an annoyance.)
Company defines up to one year as a business trip and is meant for singles. Three years for families (or singles), up to five years. After five years employees can go back, find a new international post, or localize.
I never planned on being here long, but life changes, doesn't it..I would say that 3 years is some kind of mile stone for me when weird things here turn into peculiarly interesting and little later on became familiar and cute.. The tolerance for culture shock, etc is way better if one has a job and a social network.
I would say on average I had every year one dear friend leave and return home. It sucks asS. But that happened back home too, so c'est la vie. I am more worried about it when our kiddo is older, it's sad for kids to see their friends leave. On the other hand, once one learns language it is way easier to befriend the locals (who stay).