Early drafts of great work are encouraging
sivers.org
sivers.org
A hard one is patents: you can't patent after launching, selling or even demoing it publicly, so you have to finalize the design well-enough to describe it in detail, without the benefit of experience with actual users.
You can file a provisional application beforehand, but it has to be as complete as a full application, because you can't add materially to it. I Believe that in the USA, you can apply up to a year after inventing it, but you'll still need sufficiently good documentation to be able to prove that the invention date, if challenged. A meticulously kept notebook is probably sufficient.
I think it [is] rather encouraging to would-be writers to see that someone that is [..] succesful rewrites his sentences many times. It can be quite disheartening to find it necessary to rewrite the same bit over and over again, if you suffer from the illusion that good writers pen down everything in one go.