I might be at dinner with company clients and be asked something like, "Can you start at four-thirty tomorrow morning?" I have to quickly do duty time math and determine if that will be legal, considering that I need eight hours sleep.
It's not incredibly difficult to think, "four and a half minus eight is negative three and a half, plus twenty four is twenty and a half, so that's 20:30," and thus determine that I have to be in bed by 20:30. But remember that I was probably up at four the morning before the evening on which I was asked to make the calculations. And whenever you have to do calculations through midnight it's easy to make mistakes. But thanks to Dolly Parton & Co., there's an easier way.
The theme song "Working Nine to Five" describes an eight hour work day, but for me it provides the perfect guideline for the eight hours I need to sleep. I just say it to myself in my head as "Sleeping Nine to Five..." and then adjust each end by an hour or so to match what the client is asking for. In this case four thirty requires me to get up at four, an hour before five, so I have to be in bed an hour before nine, or eight p.m. I can smile sweetly at the client and say, "Certainly, as long as we're done here in time get me back to the hotel for seven thirty."
Those of you who have philosophical objections to reporting for work at four thirty in the morning may prefer to remain at your nine to five jobs.