> I always wondered if that meant the first 90% takes 50% of the time or 10% of the time.
Essentially the latter; what you thought will be 90% the time ends up being just the first 10%. And the rest is spent on the 10% of the code, plus everything else that is part of the project besides the code: reviews, testing, revisions, deployment issues etc.
Essentially the latter; what you thought will be 90% the time ends up being just the first 10%. And the rest is spent on the 10% of the code, plus everything else that is part of the project besides the code: reviews, testing, revisions, deployment issues etc.