[toast0]

Building construction is full of last minute changes too, it's just that the scope is usually more limited. But a lot of that also boils down to the cost to make changes.

You better get the foundation of your 100 story tower right, because it's a big, costly pain to fix it later. When update costs and consequences of errors are similarly high in software, you see real effort spent on getting it right before shipping.

When costs to update are low and costs from error are low, less effort is spent on getting it right first.

Personally, I've rarely seen a specification in my career, let alone anything rigorous enough to write a formal specification from. And, even if there were a rigorous specification, everything is subject to redesign at any moment. Not a whole lot of value in formal methods in that kind of environment. You don't tend to get a structural engineer to certify your plans for an overnight camp in a two-person tent.

[galangalalgol]

I've seen plenty of specifications, and they were almost all wrong to a signiy degree. We didn't even know what was possible much less which algorithm was right until we tried it to see. We rewrote it three times using previous iterations only as copy-paste fodder before we liked how it handled real inputs. Then we updated the specification. I like this method.