**Scenario:** Let's say there are two items A and B in the product backlog of a Scrum team. From a PO point of view B has more customer value than A and is therefore ranked higher. When asking a developer for the estimated time to work on these items he gives the following input:

 - A takes 2 days
 - B takes 2 days; but if A is done before then B only takes 1 day (as some prerequisite work is done in A as well)

**Actual question:** Should estimates incorporate tasks that are shared among work item?

**Our thinking:** We've been discussing this yesterday on whether the estimates for work items should keep shared tasks in mind. Should a PO have this information to reorder the product backlog based on this information. We came to the conclusion that estimates should not contain this information, i.e. B takes 2 days time, period.

The reasons for that are:

 - The product backlog is ordered based on customer value
 - When B shares a task with A, what about the other items? There will probably be more tasks like that that need to be looked at. This will lead to long lasting discussions without a reliable result.

Are we missing sth. or is our thinking correct? There are probably more reasons to add to that list.