Is "return service requested" necessary to catch dead ends?

[Benjamin Cowles]

I've read about the use of "return service requested" in here to get the PO to send you a bill for a buck or so to get the address of an unoccupied property. Should I append that message to all my first mailings, or will I get anything returned to me that doesn't have a recipient on the other end?

I'm assuming not as we've all seen abandoned homes with full mail boxes so those aren't being returned. Is that a matter of the practices of the area and /or particular mail person? Should I just type the message on each first mailing to be safe? What do you guys do to catch as many dead ends as possible? Thanks!