> Healthcare complicates early retirement badly in the US. Retire at (say) 45 with only $2m in the bank and you are... gambling. To put it mildly. Even if you live reasonably frugally.

100% this. I'm almost 50, and as I look towards retirement, I think I should try to find a cushy job that'll last me to 65 without causing too much stress, because until you qualify for Medicare it's really hard to afford health insurance premiums unless you're fashionably wealthy.