I’m not sure when the phrase “twenty-four by seven” entered the mainstream. Recently it has grown to become “twenty-four by seven by three-sixty-five.” Which I think is wrong.
Twenty-four by seven means twenty-four hours a day, seven days a week. Following the “hours per day, days per week” pattern, the next number given, three-sixty-five, should be weeks per something. Instead it’s days per year, a retreat.
The phrase should be “twenty-four by seven by fifty-two,” or “twenty-four by three-sixty-five.”