All good points.
My initial thought was to address them to "Current Resident", in that even if they moved, there is most likely still carpet present at that location and a new prospective customer.
My interest in the location still remains regardless of who is occupying it, but I can also see the benefits of knowing if a customer has relocated, as Shane pointed out in being able to switch up the content of the message.
Probably best to just list both as Mikey says until I get my mailing routine firing on all cylinders and my customer database in order, and have a better system in place to be able to adjust mailings as necessary and mix things up a little.