Final answer:
The provided solution does not specify the required duration for keeping logs of mechanical storage or counting devices. Legal guidelines or industry standards should be consulted for accurate retention periods.
Step-by-step explanation:
The duration for which an electronic or manual log must be kept of a mechanical storage or counting device is not explicitly provided in the given reference information (Solution 5.9). The reference provided discusses the lifespan of computer parts rather than compliance requirements for record-keeping. To answer questions about record retention periods for specific industries or regulatory requirements, it is important to refer to the relevant legal guidelines or organizational standards, which can vary widely depending on the jurisdiction and the type of records.