Bah!
Many years ago I took my first contract at a small printing plant to write code in Applications Manager.
That language was a list of parameters that a central program would decipher into VT-> Mainframe applications. Not in any way man-sensible (to use a phrase current at that time).
The method of making these things was to construct a 'logic chart' of drop-thru conditions and then turn that into the code.
The department was very small, and the DPM was well-loved. He didn't use logic charts, so no-one did. And they really needed to.
I was asked to debug one of tghe programs and offered extra hours to do it, and for a week I took over a really long table (printer, remember?) and opened up the yards of greenbar carpet, crawling down it with a highlighter.
The programmer had obviously started an idea train, worked it all day, then come in the next day and completely forgotten what they were doing, so started anew. There were entire paragraphs of code that were never accessed, but it took ages to discover that with enough confidence that they could be cut out. In retrospect I should have just asked for the spec and rewritten it.
Part of the problem lay with that spec, which had several different functions bundled into what should have been a bunch of single function transactions. Well, analysts and programmers were all relatively new to the job.
Eventually I had it all sorted out on a Friday, and I left the resulting code in the library to be promoted to production, and left to take up a weekend of drinking.
Monday morning I was approached by the boss to ask if I had any backup copies.
"No" I said. "Why?"
Because my suffered-over and laboriously edited code had been overwritten - by the original mess. The mangler responsible had not made a backup of anything before they started Operation Maximum Destruct.
I shrugged and politely said there was no time now to do it over, because my contract was ending in a couple of days, which were to be filled with the finishing of my other scheduled work.