Goodness.. I think about 19. I moved a lot in my youth and then in several countries overseas. I've been here for 20 years and it's certainly the longest I've ever been anywhere. I'm staying here unless I have to move somewhere smaller in my dotage.
LOL...I have NO CLUE! A LOT! My dad was military, and we moved a bunch when I was very small. Once I turned six, we were in one city, but several homes (my mom managed motels, and most required her to live on premises) until I got married. After I married, we moved 26 times in 25. Then I got divorced and a few year later moved here. I anticipate, hopefully, one more move.
About 15, I think. Our family moved a few times. Then I made a solo move to Spain for a few years, then there were a few apartments and rental places once I was back here in CA. Hubby and I bought this house 20 years ago. We won't move again until we're too old to manage the many stairs and hills around here.