Obligatory: I Am Not A Lawyer, or a tax professional, or any kind of professional. None of the below is professional advice, merely lessons I have learned from my personal experience.<p>Well, I didn't <i>flee</i> the United States exactly, but I did move to Finland in what some would consider a hasty move.<p>It turned out to be a great decision in every regard except, of course, financially. I've probably left something on the order of $500,000 of pretax income on the table and counting at over $100,000 a year, as I moved right after completing a top university undergrad in mathematics and electrical engineering. Salaries in tech really are much lower in most other countries, even the relatively well off ones like Finland, so you need to ask yourself whether you're genuinely willing to leave so much money on the table first.<p>Another thing to keep in mind is that, due to US tax law, you will essentially never be able to invest in e.g. an index fund again. You should walk into this assuming your Roth IRA, 401k, etc. will all be essentially frozen at their current values, and that the country you move to will <i>not</i> grant them any special privileges. Nor will the US grant any special privileges to any requirement or investment accounts held in the other country. Sufficiently sophisticated investors may be able to get around this, but frankly if you're that good at this stuff you should probably become a corporate lawyer or something.<p>You may incur serious issues if you, for example, attempt to mortgage a new home in your new home. If you're fine living with one checking account and one full time job for life, forgoing any interest in entrepreneurship whatsoever, and I repeat at <i>much lower wages</i> than what you currently earn, you can probably avoid the dozens to hundreds of hours of research this will all entail. Or, you can throw money at the problem and eventually smart well-remunerated individuals will figure it all out for you. But walk into this with open eyes as to what it actually means in the worst case scenario.<p>If that's all okay with you, the good news is that most issues can be dealt with eventually if you leave with enough money and live frugally enough to get all the paperwork out of the way. I would strongly advise you to pick a handful of countries you're interested and research the passport and visa process, and to try to get that sorted out well before you actually make the move. This is not what I did, and ultimately I'm happy with my decision, but I was in very unusual personal circumstances and had to move decisively at the time or risk losing something very dear to me.<p>TL;DR: Have a lot of money. Expect to lose all of it slowly over the years and never make it back. Plan the visa/passport thoroughly. Never let it escape your conscious until everything is totally squared away. Expect the process to take up 5 to 10 years of your adult life before that happens.