Mail Greeting Name – “Dear Mr Unknown”

You have lots of contact or lead records, and you want to do a mass email or mail merge, the only problem is, some records have a first name, some only a surname, some nothing, etc. So use this as a formula field so you can choose the best way to address that person in an email/letter.
IF( LEN(FirstName) < 1,
“Sir/Madam”,
IF( LEN(FirstName) < 2,
FirstName & ” ” & LastName,
FirstName ))