[catnaroek]

> If you let the requirements drive the design rather than trying to design up-front

I don't understand this dichotomy. What kind of engineer designs anything for a third party without gathering their requirements?

[lmm]

I meant more that you need to let the things you encounter during implementation drive the design. This is particularly relevant when requirements change (as they often do), but even if you can nail down the spec perfectly up-front, trying to design at that stage is still a mistake.