I'm sure many of you remember that old show from the 60's called 'Star Trek'. A fair number of the people who wrote for the show understood things like science and engineering and yes even the military.
Unlike the 'Next Generation' where they understood none of that at all. I think in fact they were proud of the fact that the writers were all incredibly ignorant.
Now, Scotty, that immortal engineer was pretty much the icon of engineers everywhere and who performed what is often a thankless job with great skill. One of the story aspects that became a trope of sorts was how Scotty always outperformed his estimates, always went the extra mile, and always got the job done ahead of schedule. This of course led to the whole 'meme' that Scotty was just always lying about how long a job would take, so he could look good when he got it done early.
No.
What made it worse was when a moron of a script-writer working on the 'Next Generation' put that in one of the shows, because the moron had no idea how engineering or engineers work. Also, based on that Episode, Jordy sucks as an engineer and should have been shown failing in at least half the shows. Because that is the inevitable outcome of his approach to engineering - failure.
And oh, I'm an Engineer and once upon a time I actually worked AS an engineer. And also, guess what? I have been in these situations! More than once. This is one of those things that if you've had an engineering instructor in college who once actually worked as an engineer, you were taught. If you didn't you either learned the hard way, OR, some kind, older, more experienced, Engineer came over and taught you the truth. In my case wall to wall counseling wasn't involved, but I do know of instances where it was.
Here's how it goes: There is an emergency - for whatever reason - there is work that must be done and it must be done as soon as possible. An untrained person will give their best estimate, which is always wrong and they will fail miserably and either lose their job (if they're lucky) or end up facing civil and/or criminal charges (if they're not). In the military you'll be luck to avoid a courts martial.
The thing to do is first look at what the best case scenario is. Make a note. Then look at the absolutely WORST case scenario. Make another note. Now understand the worst case should take into account the environment you're working in (like, is it on fire? Is it full of some nasty substance? Are you being attacked?) all of that stuff. Also, what's the spares situation? Do you have what you need? How long will it take to get it? (and that includes sending someone either out to buy/procure something, or just run down the the warehouse/stockroom). What's the situation with you? How much help do you have? How good/reliable is it? What's their situation? Do you need more people? Can you get more people?
Now you'll be able to take that worst case scenario, and if you're experienced enough, you'll know what parts matter and what parts don't. That is probably the most realistic scenario and timeline that there is.
So you take that and you Double it. If you're really good, maybe you only increase it by half. If you're new or unsure, you increase it some more.
That's the number you give to your Captain, Commander, Boss, what have you. You NEVER, not EVER give them the best case scenario, even if they ask for it. Because that's a myth and will fail 100 percent of the time, every time. I can guarantee it. And if you give it to them, they will expect it, and then when it fails, again, your fault.
Now, here's the why of it: The person you report to is going to be making plans and decisions based on what you just gave them. If this is a critical situation, especially one where there could be injury or loss of life, those decisions need to be based on the worst case scenario. Because if they're based on the best case, and you fall short (which you will, again - guaranteed) then people are going to die and it's going to be your fault. And trust me, when the blame assignment game comes around, it will land squarely on you.
This is how engineering works. Good intentions have no place in it. Wanting to help by meeting unrealistic deadlines will get you screwed. Hoping will NOT make it so. I have quit jobs because my estimated time to complete was months past the deadline and they wanted me to lie about the schedule to make the bosses happy.
So Scotty did what he was supposed to do. He gave the most realistic answer he could, the worst case one, then he and his team went and busted ass to beat that answer. Every good Captain/Commander/Boss/etc knows this. They've probably even experienced the well meaning but inexperienced engineer way back when who always promised on the best case, and delivered on that almost half the time - and failed all the rest.
Being right half the time doesn't work in engineering, and I can show you a bridge that collapsed in Florida killing several people because they were 'often' right, but not 'always' right. History is full of such examples. Engineering is not like writing software - you have to be right 100 percent of the time. Because there are actual real world physical consequences for being wrong.