Teams definitely refine and alter estimates as new knowledge of the problem space is discovered. It’s a management (and team) failure if this does occur. Also,

Teams definitely refine and alter estimates as new knowledge of the problem space is discovered. It’s a management (and team) failure if this does occur. Also, on the negotiation side of time it will take, I absolutely know for myself that I can code things fast and functional but a bit hacky, or beautiful and elegant and will take much longer. The negotiation should be about when to do which. At a higher level, you put your teams together within their temperaments in mind and match that to the work. Some code will be a nexus of changes and interaction with other code (invest early), and some code will get written once and never seen again (go fast and forget).