States are usually based around where you are more than half the year. But that's likely simple to show. If you're actually not there they don't have much of a complaint.
This gets really messy for consulting companies, where employees "work" at the client location 3-4 days a week, 2-3 weeks a month.
We had to track and report what states we worked in and what days, down to the billing hours, and then in some cases had to file tax returns in some of those states.
Also, all of the partners were required to file taxes in every state where the company earned income, which worked out to something like 46 states and 5 countries.
The nexus is "where the work is performed" or "where the employee resides" and usually states have agreements with the neighboring states so it balances out.
https://www.njspotlightnews.org/2022/09/nj-remote-workers-ny...
Also eyeballing CA as they send us one of those mean letters you speak of. That was "fun" to sort out.
Many countries have tax law to deal with this type of American bullshit but it's still something to be aware of.
Nope, sorry, completely wrong.
You pay taxes to the states proportionately to how much time you spent in the state for the year. Many states don't even have a "floor" for how much time an employee works in a state before they're required to pay income and payroll taxes to that state, so in some states even one day working in that state triggers tax.
Consulting firms track employees time spent in each state down to the hour so they can properly pay payroll taxes. Many consulting firms will even pay for tax return prep for employees required to work in other states long enough to trigger tax compliance.
Just live in 3 different states for ~33% of the year each and you don't have to pay state taxes? Must be easy in NY/NJ/CT. :)