We had over 30,000 UA miles expire when we moved to Australia. At the time I never realised that my husband even had a UA account (no statements) otherwise I would have followed up. I'm really kicking myself now.

Another expat asked me to research his options for 90,000 BA miles due to expire. I found that if he transferred them from the USA program to the Oz program he would be entitled to another 5 years to use them.
He was very happy