A tangent but if anyone has some insight perhaps we can start a new thread.
The only tax issue was if I was out of state then our payroll folks withheld income taxes for that state instead of New Jersey. Then I had to file a return for that state in April.
I've seen companies do the above but I've also seen companies simply base everything out of your home state. You were being paid for your work out of the office in state 1 even though you might physically be in state 2 or 3. Kind of like a traveling salesman (though that's more recurring) that has clients in two or three states. So I wonder which is correct or is it based on the length of time or what?
As I understand the law, you are responsible to pay taxes in the state where you earned the money. That's why professional athletes have to file taxes in every state where they play games. Of course it's well worth the effort for Massachusetts to go after Derek Jeter every time the Yankees visit Fenway Park. Not so much when I make a one day trip to Boston.
Some states have reciprocal agreements. New Jersey residents who work in Pennsylvania pay New Jersey taxes. Likewise Pennsylvanians who work in New Jersey. The assumption is that an equal number of people cross the river each way so things even out. Not so with our neighbor to the east. New York (City and State) demands their pound of flesh. They even tax out of state residents at a rate based on the entire household income, not just that of the person actually working in New York.
I remember doing some big projects for Dupont in Wilmington, Delaware. Even though we ran the project from our office in Philadelphia and most of our troops lived in Pennsylvania or Southern NJ, and commuted daily, Dupont demanded that everyone pay Delaware taxes.