FYI A lot of the information here is no longer valid. See the IRS 2019 Publication form 463, the key part is in bold. I have no idea how much misinformation cost me this year. ðŸ˜
"Temporary
Assignment or Job
You may regularly work at your tax home and
also work at another location. It may not be
practical to return to your tax home from this
other location at the end of each workday.
Temporary assignment vs. indefinite assignment. If your assignment or job away from
your main place of work is temporary, your tax
home doesn’t change. You are considered to
be away from home for the whole period you
are away from your main place of work. You
can deduct your travel expenses if they otherwise qualify for deduction. Generally, a temporary assignment in a single location is one that
is realistically expected to last (and does in fact
last) for 1 year or less.
However, if your assignment or job is indefinite, the location of the assignment or job becomes your new tax home and you can’t deduct
your travel expenses while there. An assignment or job in a single location is considered indefinite if it is realistically expected to last for
more than 1 year, whether or not it actually lasts
for more than 1 year.
If your assignment is indefinite, you must include in your income any amounts you receive
from your employer for living expenses, even if
they are called travel allowances and you account to your employer for them. You may be
able to deduct the cost of relocating to your new
tax home as a moving expense. See Pub. 521
for more information.
For tax years beginning after December 2017 and before January 2026, the
deduction of certain moving expenses
is suspended for nonmilitary taxpayers. In order
to deduct certain moving expenses, you must
be an active member of the military and moving
due to a permanent change of duty station. "
