A careful first attempt can still contain uncertainty that only use reveals.

Care at the making stage cannot answer every question. Some things only show themselves once an object is used by someone who was not thinking about how it was made: where it slips, where it tires the hand, what people do with it that you never imagined. That is not a failure of attention beforehand. It is a different kind of information, available only afterwards.

Get the careful version into real use sooner rather than perfecting it further in private. Then ask the user what surprised them, and treat the answer as the next stage of the making rather than a verdict on the first.