Nobody is ever 100% sure. The only thing you can really be sure about is the software will be required to change in ways you have not yet imagined. I've become

Nobody is ever 100% sure. The only thing you can really be sure about is the software will be required to change in ways you have not yet imagined. I've become wary of the "you won't need it" attitude. In my experience, tomorrow rarely arrives. If you don't put work into your architecture up front then you'll just end up building a ball of mud. It's even worse if you've got junior developers who very much code by example.