I always phrased this as "You don't know how to build something until you've built it." It's very easy to get stuck in design hell and write yourself into a co

I always phrased this as "You don't know how to build something until you've built it." It's very easy to get stuck in design hell and write yourself into a corner. It's much better to get something that does what you want, then you change it to do it how you want it to. Though like others have mentioned, this requires an engineering culture that values the second part.