You might not live where you think, at least as far as the IRS is concerned. There are a lot of different rules when it comes to residency. US citizens and Green Card holders that move outside the US are still taxed on all their income in the world, even though the US is one of the only countries with this rule. Similarly, nonresidents of the US can be considered tax residents if they spend six months, or even just an average of four months a year. Some of these rules can be modified if you claim the right relief, but to do that you have to file a US return. And remember, income from the US is always taxable by the US, especially retirement plans and real estate. Our recommendation: Don’t blow off the IRS because you don’t think you have ties to the US.