Virginia law generally requires you to maintain transaction records for at least three years (§54.1-2110.1 / 18VAC135-20-165).  When that three-year period begins depends on the type of record.

• Three years form the date of execution for brokerage agreement, each disclosure and consent to dual agency or dual representation, and each disclosure and consent to designated agency or designated representation;
• Three years from the date provided for each disclosure of a brokerage relationship to an unrepresented party shall be retained for three years from the date provided to the party;
• Three years from the date of closing or ratification, if transaction fails to close for each executed contract of sale, any executed release from contract, any executed lease agreement, any executed property management agreement, and each settlement statement related to a real estate transaction, in the broker's control or possession;
• Three years from the date of the closing or termination of the sales transaction or termination of a lease or conclusion of the licensee's involvement in the lease for receipts and their disbursements for moneys received on behalf of others.

Depending on the circumstances, best practice would be to retain records through the expiration of any applicable statute of limitations.  For written contracts, an action must be commenced within five years of execution or the accrual of the cause of action.