Subject to the terms of this retainer agreement, in the event any bill from this firm remains unpaid beyond a 30-day period or, if in the judgment of this firm. This client Retainer Agreement is for ongoing service agreements between a client and consultant or contractor.Sample Retainer Agreement. "Deferral Plan") for any year could have all or any part of either the cash or stock portions of the director's annual retainer fee for that year deferred. This agreement for legal representation is between, AGENCY NAME, and CLIENT(S) NAME(S).