48 CFR §4.705-3

1. (a)Store requisitions for materials, supplies, equipment, and services: Retain 2 years.
2. (b)Work orders for maintenance and other services: Retain 4 years.
3. (c)Equipment records, consisting of equipment usage and status reports and equipment repair orders: Retain 4 years.
4. (d)Expendable property records, reflecting accountability for the receipt and use of material in the performance of a contract: Retain 4 years.
5. (e)Receiving and inspection report records, consisting of reports reflecting receipt and inspection of supplies, equipment, and materials: Retain 4 years.
6. (f)Purchase order files for supplies, equipment, material, or services used in the performance of a contract; supporting documentation and backup files including, but not limited to, invoices, and memoranda; e.g., memoranda of negotiations showing the principal elements of subcontract price negotiations (see 52.244-2): Retain 4 years.
7. (g)Production records of quality control, reliability, and inspection: Retain 4 years.
8. (h)Property records (see FAR 45.101 and 52.245-1): Retain 4 years.