Square is one choice. Sometimes it works. Sometimes it doesn't. But if I have a camera that shoots a square ( = all my cameras except 35mm and 5x7) I aim for the print to be square for no particular reason.
For me the choice is more about how the pictures look on the wall, together. When I shoot with a square format, I try to make the square work.
Yet, if the square doesn't work, I don't mind cropping either.
Whatever the situation takes I'm willing to put up to make it work in the print.