[johnwalkr]

Good requirements include margins. In aerospace it's common to see[1] a system requirement that says "...shall supply a peak current of 1.0A for 1.0s", a general requirement somewhere else that says "...power supplies used for the purpose of X shall be designed to a margin of 1.5 for current and a margin of 2.0 for time", and a child of both that says "...shall supply a peak current of 1.5A for 2.0s, including margins".

That being said, I work in aerospace and if a company aims to meet the above requirements but maximimize or minimize some aspect, e.g. make a light/cheap/competitive product, how do you do that? There's always a few engineers that will die on the hill of "but there is no requirement for mass of this particular component" or "you said I should minimize mass but that's not a real requirement" (many organizations reject anything but "shall requirements" when it comes to formal review). TBC or TBD values can be used, but then it's difficult for everyone to understand if the value is a target or just something to be updated later. On the other hand, there's always a few engineers who will happily work for an extra year to optimize something way too much.

Sometimes a requirement is flat-out incompatible with another requirement, too. Requirements are so important but they are just a tool, and also sometimes require iteration. Number 38 goes in the right direction, but I would personally want to add "46. Sometimes requirements are wrong".

[1] These are simplified examples

[elteto]

A 1.5 factor of safety in aerospace? Outrageous. I’ll give you 1.1 and I’m being generous!

I’m kidding…