I do not necessarily think that there are advantages versus disadvantages to these two documents as they both offer very crucial yet distinct purposes. The Design Input Document serves to provide the basic customer needs while the Design Specification Document includes the specifics of the device. However, there must be a DID for there to be a DSD. Additionally they are needed for validation and verification in Design Control.

When completing design verification, the DID is used to verify that the device meets the requirements set by the customer. Verification ensures that all the customer needs are addressed through checking if the inputs have an output. If the device fails verification, then the DSD must be reviewed, investigating the specifics of the device. Once the verification and validation report is completed, the results are documented in the DSD. Verifying and validating a medical device necessitates the need for these two documents, providing information for the development of the device.