Beware the UPS Store (or Mailboxes Etc or similar) mailbox 2014
Warning: If you sign up for a mailbox at a non-USPS location, you will not ever be able to file a change of address for it with the postal service.
Also, it's probably a franchise, meaning UPS (with their potentially-consumer-benefiting concerns about maintaining their brand) has no control over pricing, meaning the store might decide to double the fee for that mailbox at some point and leave you with a tough choice.
CRMAs are required to offer mail forwarding services for six months, but they can (and do) charge for them. So far as I am aware UPS Stores do not offer forwarding for a closed box for longer than that six month minimum.
Yes, it's nice to have a non-home-address to use for business or other purposes, but be aware that there are serious flexibility issues with signing up for CRMA (Commercial Mail Receiving Agency) services.
Update July 25, 2014: Just spent 51 minutes on the phone with USPS. The person I spoke with said her supervisor told her that you can put in a change of address from a CRMA address to a street address or USPS P.O. box. I'm going to try that and hope it works.
My particular UPS Store, while not bending on their pricing which is now 4x the cost a USPS box, did say that it is their policy to hold mail from terminated boxes for a little while and to turn it over to the former box owner if they check in, after which they return it to the postal service. It is unclear what would happen to that mail then. It's already been delivered, but maybe a change of address could kick in.
But no. After trying to submit the change of address, I got this on the USPS website:
"Mail addressed to an addressee at commercial mail receiving agency (CMRA) is not forwarded through the USPS. The CMRA customer may make special arrangements for the CMRA operator to re-mail the mail with payment of new postage. A CMRA must accept and re-mail mail to former customers for at least 6 months after termination of the agency relationship. After the 6-month period, the CMRA may refuse mail addressed to a former customer. The Application for Delivery of Mail through Agent (PS Form 1583) requires an addressee and agent to comply with all applicable postal rules and regulations relative to delivery of mail through an agent. For more information on mail forwarding regulations, contact your local Postmaster."
I have not been offered any mail forwarding service from the UPS Store and it sounds as though they would immediately put in a termination notice with USPS for accepting my mail. Not sure what that means would happen to any of my mail, but seems as if it would be destroyed or returned to sender.