But here are few things that will impact the accuracy:
- how familiar are you with the technology - how quickly the dependencies change (tech dependencies). - how technical your project manager is - you will likely to spend more time in the meeting explaining some trivial stuff if PM isn't technical. - how many visual design revisions you need to implement during this estimate - how big is the task - if it's bigger than 2 days your accuracy drops.
My advise is to keep the tasks small, no more than 2 days (3 days or 20 hours max). And total phase smaller than around 200 hours. You also need to make sure that everyone is on the same page - if there is no good communications your estimate might need to be revised during the development phase.
Even if you implement the same project the second time - it still not guaranteed to be faster than the first project.