I remember some of our fab folks, operators and techs I think, were on a 3 on 4 off rotating schedule. Talk about disrupting family time. I was thankful I didn't have to deal with that kind of disruption. To provide technical coverage for all production shifts, engineers were on call 24/7 (uncompensated). I had a pager and/or a cellphone on me at all times. Fortunately I rarely experienced those emergency calls, maybe once a year and was able to resolve the problem on the phone without driving back to the plant. Still, it was very unnerving to hear the pager go off, followed by the cell phone and if that didn't wake me up, the house phone too.