the thing with startups as founder / founding teams is that most days are actually good stories - so yes, the best way is to write as you go.
the thing is perhaps this is in fact the best way to motivate (or demotivate) the startup craft - you end up learning by drinking from the firehose daily. I believe there are few other types of activities that have such a forcing factor to learn and most are generally some sort of crisis (war, etc.) and so entrepreneurship is likely the least damaging one (at least for everyone else than the team haha)
the thing is perhaps this is in fact the best way to motivate (or demotivate) the startup craft - you end up learning by drinking from the firehose daily. I believe there are few other types of activities that have such a forcing factor to learn and most are generally some sort of crisis (war, etc.) and so entrepreneurship is likely the least damaging one (at least for everyone else than the team haha)