I work some where that does double shift which is mornings one week and afternoons the next. It's OK but id prefer standard days, I have however done triple shift for a year at one job and it completely messed me up, and to this day I blame it for giving me super high blood pressure I didn't have before I started it. It all comes down to profits, why buy another machine to manufacture whatever it is you do when you could simply run the same machine 24/7. Although it inevitably leads to disaster one machine doing all the work as triple shifts leave little time for maintenance and seeing managers flap about because a machine broke down because you were allowed to shut it down to grease the bearings once a week is hilarious.