For me personally, I am not tied to amy format unless the patron paying for my services requests a horizontal, vertical or square. I try to fill the frame and at times have been burned by the square format of the Blads. Tough to crop to a 8x10 print with a full frame 6x6. Many magazine covers are square,
but many also request Verticals and a few even horizontal. I try to cover all the bases when I am not sure how a shot is going to be used, by shooting the subject in such a manor it can be cropped to any shape an editor chooses.
For my own work, I let the subject matter dictate or guide me in how it best can be rendered. I do not pretend to be an artist, just an image maker.