why: so the government won’t be able to use your money for whatever the fuck they’re planning for the next 4 years.
as a traveler, none of my money has been funding Israel, for example.
one-step method: you basically fill out one extra tax form called FEIE while you’re doing your taxes, write down the dates you were outside of the country, and then since you aren’t in the country and are not receiving any services from the US, you don’t have to pay income tax up to a certain amount (it’s a little over 125k this year).
Yeah, some is specific to Japan, though there will be similar hurdles anywhere the US has an agreement (and that the target country’s institutions actually follow it, I suppose).
I have a couple of retirement accounts in the US that I contributed to before (I moved overseas in my early 30s) that I basically can’t touch for a number of reasons right now. Just wanted to throw it out there.