A couple years ago, the company I work for created a spreadsheet employees could use to track their vacation time. At the time, I was doing some of the administrative functions for my team while we were temporarily without a manager. I took the company spreadsheet, and altered it so that the entire teams vacation schedule was on the same spreadsheet. We’ve used the team spreadsheet ever since.

The other day, my boss asked our secretary to turn the spreadsheet around for next year. She came today to ask for help with her changes.

“I think I messed it all up,” she said. “I had trouble inserting columns in the spreadsheet and I goofed it up.”

“But the columns in the spreadsheet are days of the week,” I told her. “They are ‘Monday’, ‘Tuesday’, ‘Wednesday’, ‘Thursday’, ‘Friday’. What were you going to insert?”

She couldn’t answer that one, so I can’t tell you what those new days are.

But it reminded me of a few years back when I was working from specifications that said the DAY_OF_WEEK field should be a two digits. I asked my coordinator what the DAY_OF_WEEK field represented.

“It represents the day of the week. Zero is Sunday, one is Monday, two is Tuesday, etc.,” he told me.

“OK. There are seven days. Why is it a two digit field?”

Without missing a beat, he replied, “In case we ever decide to add additional days.”

Now there’s a man who plans ahead. So, if we ever decide to go to a metric ten day week, that system will be able to handle it. And after our secretary has inserted a few columns on the team vacation spreadsheet, it can handle a metric week as well.