I personally think that what you are saying, and what I am saying, is not mutually-exclusive at all.

Certainly, some tasks need to be done during “other shifts,” specifically so that they do not impact the first-shift activities.   (And, in an Internet that works around-the-clock, “it’s eight o’clock somewhere.”)   (Reference to a Jimmy Buffett/Alan Jackson hit song.)   There can indeed be great advantages to working a shift that overlaps nine-to-five.

I am quite confident, BrowserUK, that you are experienced enough to have planned your own work (and/or your own team’s work) very well, even if the hours worked were unconventional.   It is easy to know from hearing you “speak” that you have been around this block many times:   yours is the voice of well-seasoned experience.   The particular situation that I was speaking of is a different one:   lack of planning, both before and during the execution of the project.   (As you well know, a project that is designed to have staged-deliverables and prototype deliverables must be planned before and during its execution, even more carefully and nimbly than other projects must be.)

I just had the very unpleasant experience of being close-at-hand to what turned into a one-month long train wreck.   It was a very time-consuming data load process for a production system; a process that indeed would take several weeks, and it should have had two weeks to spare.   But no one took the time to make sure that all of the files to be loaded were in place, that they were the correct versions, or that they were not corrupt.   No one took the time to make sure that tablespaces were big enough, nor that temporary space pools would not be exhausted, even though this was a monthly process that had been done many times before.   (Apparently it was always like this.)   And so the train-wreck happened, I surmise, again.   Steps were running for days and then crashing.   One step after another after another, and it obviously could never have been otherwise (for entirely predictable, technical reasons).   “This thing’s gonna blow, because it cannot possibly do anything else...”   I frankly could not believe my eyes.   What was the subsequent demand?   You guessed it ... overtime.   What possible good it would do I know not, but very single person on that team was expected to throw their lives to the wind for the duration.   “Ride up to the front with our horses and lances and try to dodge the machine-gun bullets as we battle heroically save the day.”   There was no planning, only reacting ... like having one’s head stuck in the middle of a gumball machine.   It was the damndest thing to watch, and a certain Billy Joel song was running through my head.   It happens.   Frequently.

I know that, for myself as for anyone else I have ever worked with, mental fatigue is a critical concern.   (And as I get older, my stamina is not what it used to be.)   You can get tired, and your concentration goes to hell, and you go into what I call, “stupid mode.”   I know from experience that the only thing to do is to “take a backup now, and get the hell away from the keyboard.”   No drinks, no coffee.   Read a book and go to sleep before you do any serious damage... because you will.