In the late 80s, I worked on the mainframe team. One of my teammates, Izzy, was told that he’d also have to work on DEC/VAX equipment.
Izzy wasn’t very happy about this. He was quite content to keep working on mainframe equipment and saw this as a bit of a demotion.
“Not to worry,” he was told, “It’ll only be 10% of your workload.
Within a few months, he was spending all of his time on the VAX and no time on the mainframe.
Izzy figured that they’d assumed a 400 hour workweek when they said 10% of his time.
A few years later, Volkswagen sh*tcanned the entire IT department and Izzy found that his VAX skills were in much more demand than his mainframe skills.
Then again, neither VAX nor mainframe skills are wanted any more.
There was a point in all of this somewhere but I can’t think of it.