I use them, they rarely come up in 3e though.
In a new campaign I am co-DMing however, I expect it to come up a bit more. The characters' world was being destroyed by "mists" which consumed everything they touched; cities, forests, etc. The town they were in managed to create a shield that kept the mist away, but when it was lowered a few weeks later (air was running out), the whole landscape had changed.
(Town was in a prairie, now an island off a wooded coast).
The party doesn't know what happened or where they are, one theory is that the city moved through time, in which case, some demi-human NPCs might still be around but older (or younger). Also, one of the PCs (a human) has plans to clear some land on the continent, become a lord, found a line, etc. It may take him a long time to do and he could be middle-aged or more before that happens.