[rednab]

The way I've explained this to coworkers and stakeholders is, "A prototype costs 1x, a product costs 3x, and a platform costs 9x."

Not exactly the definitions Brooks used, but memorable and in my experience surprisingly accurate.

[skeeter2020]

I've built a few products from idea to commercial software, and IME Brooks was being generous, as anecdotally I always pegged it at closer to 4x, but then I'm slow. It's actually really surprising how few product managers (forget about developers!) don't seem to know this, yet they also tend to push out the initial release way too far, so you get half a product late, then move on to the next thing.

[hgsgm]

3 is far too small.

[didgetmaster]

Agree. 10x at each stage is more realistic.