Wow. When I did this in the 1980s, it was $250K (minimum), in 1980 dollars. Things have gotten easier! :-) There was the situation where if you didn't become a

Wow. When I did this in the 1980s, it was $250K (minimum), in 1980 dollars. Things have gotten easier! :-) There was the situation where if you didn't become a citizen (which was hard, but not impossible, at the time), you could visa-work your way throughout 40-or-so years of employment, but if you weren't a citizen, you were booted at 65, even if you had paid in your whole life. Fun times.