I've worked on about 10 different teams using some variant of Agile, and I only recall one which was able to achieve accurate estimates for a complex software p

I've worked on about 10 different teams using some variant of Agile, and I only recall one which was able to achieve accurate estimates for a complex software product... What's the secret? Story points are only the beginning. They are an estimate which must be updated during the planning meeting. Our planning meetings for a team of fewer than 10 people took the better part of an entire workday -- 8 hours. What we did during those meetings was pick apart the user stories into small developer tasks until there was no task larger than 3 story points on the board, ideally all of them one-pointers, with one point being an estimated 1 hour of work. We also spent most of an entire day for each retro meeting. Edit: Our definition of done was signed off by the QA Engineer.