D18 is at an OOS public in a state with a much lower income tax rate (and the new standard $12000 personal allowance). She'll have taxable scholarships from that state which wouldn't exceed her personal allowance there. But our home state (CA) didn't conform to the new federal tax code and has a much lower personal allowance (and I'm assuming she could presumably be liable to kiddie tax on her scholarship as unearned income at a state level, which would be quite a lot of money, perhaps $1000 per year in 2019).
However, she is staying at school this summer and probably the next few summers as well and will have an apartment there for next year and subsequent years - she'll spend less than 30 days in CA this tax year and all the work she does for her summer job will be out of state. She already registered to vote in the other state when she turned 18, and can change her drivers license, addresses on bank accounts, etc. (although hasn't done so yet and she has borrowed our car to take to college, which still has a CA registration). I would be quite surprised if she moved back to CA after college, since its so expensive here.
So I'd be keen to hear advice from other people whose kids moved their tax residency to another state while in college. What steps did you take, when did you do it, how did it work out?