How long must a lawyer keep client files?
Absent any obligation to retain a client's file imposed by law, court order, or rules of a tribunal, a lawyer shall securely store a client's file for a minimum of six years after the termination of the representation unless: (1) the lawyer delivers the file to the client or the client's designee; or (2) the client authorizes destruction of the file in a writing signed by the client, and there are no pending or threatened legal proceedings known to the lawyer that relate to the matter.
SCACR 417 (Financial Recordkeeping)
South Carolina Bar Ethics Advisory Opinions: 02-14, 98-33, 92-19
Wilcox and Crystal, Annotated South Carolina Rules of Professional Conduct, pp. 168-169.