To determine whether computer cables need to be replaced, the following aspects can be considered and checked:

1. Appearance inspection: Firstly, the appearance of the cable can be observed to determine whether it needs to be replaced. If there are damages, deformations, aging, discoloration, or obvious signs of wear on the surface of the cable, it may be necessary to consider replacing the cable.
2. Performance testing: Instruments and equipment can be used to test cables, measure their insulation resistance, transmission characteristics and other parameters, and determine whether they meet standard requirements or design specifications. If the test results are not satisfactory, it may be necessary to replace the cable to ensure its normal operation.
3. Usage time and environment: Consider the usage time and environment of the cable. If the cable has been used for a long time or in harsh environments (such as humidity, high temperature, dust, etc.), it may be necessary to consider replacement in advance to avoid potential safety hazards.
4. Signal transmission quality: If there is obvious distortion, delay, or interruption in the cable during signal transmission, it may be an internal problem of the cable that needs to be inspected and replaced.
5. Connection stability: The stability of the cable connection is also an important factor in determining whether it needs to be replaced. If the cable frequently experiences poor or loose connections, it may be necessary to replace the cable with a new one to ensure the stability of the connection.

Overall, in order to ensure the normal operation of computer systems and data security, it is necessary to regularly check the status of cables and determine whether cables need to be replaced based on actual situations. Meanwhile, when replacing cables, reliable and standard products should be selected, and the correct installation and use methods should be followed for operation.