It would be great if Tableau include the ability to either map, or export (to access, excel, and visio) the information needed to map dependencies between calculated fields. As far as I've been able to tell, the dependencies are listed at the bottom of the calculated field edit box, but as soon as you have more than a few, I don't see a built-in way to copy or use the full list of dependencies within the Tableau (supported) environment. [With deference to Andy's TWB auditor tool here]
In my ideal world, I'd have the data needed to build dependencies maps in Visio, for example:
That way, if someone changes the definition of what needs to be in a particular calculation, I can easily track what needs to be changed, and what else will be affected. For example, if the Net calculation is changed to include another overhead expense that wasn't included before, I'd know that I have to change it for all four of my Expense time buckets, and I'd know that all four Net calcs and all four net/item calcs would be affected by the change. On the other hand, if we needed to change the dates of the marking program (the end of the "during", and start of the "After") then I could see which downstream measures would need to be revalidated, without having to manually document all this, or navigate through all the measures in the workbook to work out the dependencies.