I think it depends on the size/scope of what you're doing, how complex it is, and how much novelty (technical and domain) there is in it. For things that are n

I think it depends on the size/scope of what you're doing, how complex it is, and how much novelty (technical and domain) there is in it. For things that are not terribly new, are small enough to knock out with 1-2 devs, and aren't massively complex, just writing some damn code works really well. But the larger it gets the more useful it is to do some thinking beforehand, especially about the overall architecture, technology choices, potentially tricky error cases, etc. Also it can be particularly useful to flesh out public/widely-used APIs and data storage details, as those tend to be difficult to change once put in place. That said, I don't think a fully fleshed-out "specification" is useful in most cases. A wiki page, or maybe a few, is usually enough. You just want to spot major problems far enough ahead that you can avoid them instead of running into them. But hey, YMMV, this is just what I've found. TBH I wish it was different, because I actually _like_ hacking out code more. It's just that thinking ahead _works_ better IME.