It was also common before Pope St Pius X's reign (early 1900s) to only receive Holy Communion once a week. I could see how a couple/family could prepare their weekly schedule to revolve around Sundays and so prepare for Holy Communion with such conjugal fasts. Then St Pius X came along and encouraged daily communion. How then could a couple plan their week around daily mass, or even a spur-of-the-moment "I'm going to wake up tomorrow and go to early mass at 6am before work"? I think it's a great idea, but not sure how it works, practically.