The goal of this approach was to have an intuitive way to enter multiple phone numbers and email addresses per contact or lead record:

The logic is driven by 4 workflow rules:

1. When ‘Do Not Call’ = TRUE, update Phone to NULL.
2. When ‘Email Opt Out’ = TRUE, update Email to NULL.
3. When ‘Do Not Call’ = FALSE, update Phone:
   IF(TEXT(Preferred_Phone__c) == "Home Phone"
   && Home_Phone__c != ” && Home_Phone__c != NULL, Home_Phone__c,
   IF(TEXT(Preferred_Phone__c) == "Mobile Phone"
   && MobilePhone != ” && MobilePhone != NULL, MobilePhone,
   IF(TEXT(Preferred_Phone__c) == "Work Phone"
   && Work_Phone__c != ” && Work_Phone__c != NULL, Work_Phone__c,
   IF(TEXT(Preferred_Phone__c) == "Marketing Phone"
   && Marketing_Phone__c != ” && Marketing_Phone__c != NULL, Marketing_Phone__c,
   IF(TEXT(Preferred_Phone__c) == "Other Phone"
   && Other_Phone__c != ” && Other_Phone__c != NULL, Other_Phone__c,
   IF(TEXT(Preferred_Phone__c) == "Other Phone 2"
   && Other_Phone_2__c != ” && Other_Phone_2__c != NULL, Other_Phone_2__c,
   IF( Home_Phone__c != ” && Home_Phone__c != NULL, Home_Phone__c,
   IF( MobilePhone != ” && MobilePhone != NULL, MobilePhone,
   IF( Work_Phone__c != ” && Work_Phone__c != NULL, Work_Phone__c,
   IF( Marketing_Phone__c != ” && Marketing_Phone__c != NULL, Marketing_Phone__c,
   IF( Other_Phone__c != ” && Other_Phone__c != NULL, Other_Phone__c,
   IF( Other_Phone_2__c != ” && Other_Phone_2__c != NULL, Other_Phone_2__c,
   ”)))))))
   )))))
4. When ‘Email Opt Out’ = FALSE, update Email to:
   IF(TEXT(Preferred_Email__c) == "Personal Email" && NOT(ISBLANK(Personal_Email__c)), Personal_Email__c,
   IF(TEXT(Preferred_Email__c) == "Work Email" && NOT(ISBLANK(Work_Email__c)), Work_Email__c,
   IF(TEXT(Preferred_Email__c) == "Marketing Email" && NOT(ISBLANK(Marketing_Email__c)), Marketing_Email__c,
   IF(TEXT(Preferred_Email__c) == "Other Email" && NOT(ISBLANK(Other_Email__c)), Other_Email__c,
   IF(TEXT(Preferred_Email__c) == "Other Email 2" && NOT(ISBLANK(Other_Email_2__c)), Other_Email_2__c,

   IF(NOT(ISBLANK( Personal_Email__c )), Personal_Email__c ,
   IF(NOT(ISBLANK( Work_Email__c )), Work_Email__c,
   IF(NOT(ISBLANK( Marketing_Email__c )), Marketing_Email__c,
   IF(NOT(ISBLANK( Other_Email__c )), Other_Email__c,
   IF(NOT(ISBLANK( Other_Email_2__c )), Other_Email_2__c,
   "")))))))

   )))))

You could probably combine these into 2 workflow rules per object as well.  This was driven with inspiration from the Non Profit starter kit, which uses a similar contact management strategy (although allows update of standard phone/email fields).

How do you handle multiple phone/email addresses in your org?  Have you found a better way?  I want to hear about it!

Cheers,

John