I have a friend who lives and works in two states. They work at two facilities in two different states for the same company, and have shared apartments near both facilities. I already know there are tax forms to declare part-time residency in both states. But what about other residency issues?

They switch back and forth fairly often (at least once a month on the average), and overall, they spend about half their time in each state. Can and should they have a driver's license in both states? Can they register to vote in both states? What about college tuition? Could they be considered a resident of both states for college tuition rates?

I'm sure there are many other issues I haven't thought of where state residency is an important issue. When they have to choose, can they choose different states for different purposes, or could this get them into legal trouble?

They would have to set up a primary residence. This will be their home base. This is where they would vote. You can not be registered to vote at two separate places. You can only have one drivers license. Your auto will be registered here as well. This would be from the state of your primary residence. Colleges charge a higher fee for non residents. The school would base their fee on the primary residence. If they make money in both states they have to file a tax return with both states.

see here

Thanks for the info and the link, both of which are very helpful. I'll pass both of them on.