In the ‘70s, we wrote a PL/1 BNF parser to update Fortran to Fortran77. It soon became apparent that it would be easier to enhance if we wrote it in itself, and someone immediately wrote the inverses to check both. That did it. Soon there was a competition to create the longest loop through the most languages to produce functioning code, with extra points for generating similar code with the same variable names. The project was still going in late ‘82 when I left.

You have to take an historical average. In the ‘70s, I bought an HP 10c calculator. I was so enamored of RPN that I bought another so I could carry one in my briefcase (we used those, too). I do not remember if I ever had to even change the batteries except once when I was fiddling with it and dropped one of the buttons under my desk. I still use both of them, even for *date* calculations. And then there is the CP2025 laser I bought in 2008, which has never even jammed. HP is just making up for accidentally making unprofitably reliable things for years.