E-mail Functionality in Customer Master Data

Dear All,

I need a clarification on the E-mail functionality used in SAP.

We have Email fields available in Address tab and Contact person tab, in which scenario these fields to be used. For ex: Today my client is maintaining multiple mail ids in Address tab by giving serial nos when we asked them to move it to contact tab they raise a question why it needs to be changed because in Address tab they are maintaining multiple ids with different notes(order,invoice etc) and program identifies the mail id with the notes.

Any recommendation Standard SAP suggests to use only the contact mail ids - PLease share your thoughts

Thanks in Advance

Saravana