I did this years ago in a hospital setting. At first we thought it would be better for covering patients (dietitians) and it would help us have longer options when we had to cover weekends.

However, it was harder to have continuity with the patients, and we did feel more tired those long days. We went back to 5 days a week.

I was in my 20s and that was a long, long time ago. It had nothing to do with reducing energy costs.

One thing I have learned over time is that everything changes. Remember when the stores were closed on Sundays?