Family Names: Too close for comfort?

Today’s Question of the Week concerns family names:

Would you use a name that’s the same as, or very similar to, one used by another family member? 

Would it depend on the closeness of your relationship—is it different for a sister’s child than it is to a second cousin’s?

Does it depend on geographical distance—say if your Declan would be growing up in Boston and your cousin’s Declan lives in Denver and they would rarely get together?

How about closely-related or variations of the same name, eg Sophie/Sophia or Asher/Ashton or Bella/Isabella—in other words names similar enough to confuse Great-Grandma?

And would it be different if it were a common name (I have several Sarahs in my family, for example) or a more unusual one?

Would you talk it over with the other family members before making a decision?