Don't Let the Co-Signer Off the Hook!
Most property owners get into trouble when they make changes to the lease with out the co-signers written approval. This can be adding or deleting a person to the lease. Adding pets to the lease or even renewing the lease if the co-signer does not sign the new lease.
How do you avoid problems? Its easy, just make sure you get the co-signers signature every time you make a change to the lease agreement.