[yapcguy]

Worth adding that most expats probably want to live a 'normal' life in their adopted country.

That means using local bank accounts / credit cards, getting a mortgage, etc.

Being resident and working probably means the state will automatically open social security and pensions in your name.

Also, expats still have to do the tax return for their adopted country, and the tax year may not be based on a calendar year so they can't just re-use the same figures!