How long were they half-staffed for Justice Scalia when he was murdered?
That's exactly the question that came to my mind.
So, I looked it up. What I found was tradition and/or presidential proclamation says for a departed associate justice of the Supreme Court, flags shall be at half-staff from the day of death until interment.
At my house, soon after I hear RBG has begun to assume room temperature, I plan to fly the Gadsden Flag again (and not at half-staff). :-)