>My experience is that developing against fixed requirements is fast and produces exceptionally high quality code. So many bugs and so much technical debt is from having to rewrite the same thing over and over because the requirements aren't set when development starts.
I think that's why Agile was invented: for situations where requirements are not fixed. If you have fixed requirements, I don't see why you'd need Agile development in the first place, though some parts of it might be useful for just keeping everyone on track.
In a recent job, we used Scrum and it generally worked well, but we didn't have the luxury of fixed requirements. The customer needed new features on a regular basis (features which they could not have foreseen the need for beforehand), and we'd regularly give them deliveries of the version of the product we had, which they'd immediately put into use. A waterfall model would never have worked there.
I think that's why Agile was invented: for situations where requirements are not fixed. If you have fixed requirements, I don't see why you'd need Agile development in the first place, though some parts of it might be useful for just keeping everyone on track.
In a recent job, we used Scrum and it generally worked well, but we didn't have the luxury of fixed requirements. The customer needed new features on a regular basis (features which they could not have foreseen the need for beforehand), and we'd regularly give them deliveries of the version of the product we had, which they'd immediately put into use. A waterfall model would never have worked there.