When I first joined the Web Services Group of the I.T. company I work for seven years ago, my boss advised me to learn and use the 24-hour clock. The reason being if I used it in my schedules and reports to clients (most of whom lived on the other side of the world) there would never be any ambiguity about time.
This never had any real impact on the way I kept time until we had to schedule downtime for one of our client’s web servers a few years ago. The agreed time was 1:40, or so I thought after having read the email from my boss regarding the schedule.
So there I was that afternoon on the webmaster’s pc, happily pushing buttons on PC Anywhere taking the servers down as per schedule. Not ten minutes later I get an overseas call from the client, screaming what the f*ck had happened to his website. I told him about the downtime. He said he knew about the downtime, and that it wasn’t supposed to happen until 12 hours later, when his users in the western hemisphere were asleep.
I looked at the email again and realized my mistake. He meant 1:40AM — if he had meant 1:40PM he would have said 13:40.
I apologized profusely to my client and proceeded to bring his servers back up again. It was a good thing that a few mouse clicks could rectify my mistake, and that the client decided that the downtime that resulted from my mistake was not long enough to have caused a loss of income for him and therefore he would not sue our company.
Since then I configured the clocks on all the computers to which I had access on 24-hour time format. Better safe from now on than sorry again.