That is great advice. Whenever I'm about to build something big, I first start thinking about things that would be hard to do, or perhaps that I even don't kno

That is great advice. Whenever I'm about to build something big, I first start thinking about things that would be hard to do, or perhaps that I even don't know how to do yet. Then I build prototypes of those to make sure I can to it and do it efficiently. Once all pieces are ready, it's just a matter of putting them together which is straightforward and you have some chance to actually estimate the time.