1. Do we file a lien on the retainage amount? We are finding that our customer is holding the retainage out of each invoice. It was our understanding that the retainage letter covered us so that we would not have to file a lien on just retainage 2. Do we file a lien at the end of the 4th month per invoice or at the end of the job stacking all of the invoices for that whole job?