Originally Posted by
revelo
This is different from what you wrote above, regarding the OP. According to your original post, a person currently living in the UK whose last domicile in the US was in PA, is still considered to have PA as her US domicile. If she wants to avoid filing PA taxes, she should establish domicile in one of the states that does not have a state income tax (Nevada, Wyoming, Texas, Alaska, South Dakota, etc). Some states tax dividends and interest but not earned income, that may or may not be an issue.
As for filing taxes while traveling, what is wrong with Turbotax? The online version is very easy to use and comprehensive. You can also use eftps.gov to pay estimated taxes automatically.
You are confusing domicile and residence.
Someone can be domiciled in a state, but resident somewhere else for tax purposes and therefore not required to file a state form. The states you mentioned are often used by RVers so that they can avoid state income tax and it would probably be a good idea to become resident in one of them if you planned to become a "Perpetual Traveler" like the OP, but for most people moving abroad it isn't necessary as they will become resident in a foreign country and thus have no need to file US state taxes.
The lady from PA is probably still domiciled in PA, if that's where she was born and the majority of her family still lives. However, as she has married and moved to the UK and become UK resident there is no PA tax filing requirement unless she has PA source income. She may well be able to change her domicile to the UK as she develops substantial links to the UK. A common test is to ask someone where they would go if they got divorced or their spouse were to die.
For the OP his domicile may well be AZ, but it might be somewhere else depending on where he was born and his family history. But assuming AZ domicile, if the OP hasn't spent long enough in one place to become resident in another state or country then he will still be required to file AZ taxes.