Validation is always an important step in the Design Controls. However, it is not necessarily always needed if there are no changes like you mentioned. Although that might be the case, I feel that a human factors evaluation should still be done. The evaluations are necessary to understand the interaction between the person and the medical device. There may not be any changes to the product, so it may seem pointless to do the evaluation. However, this could people’s lives at risk. If the human factors evaluation is not completed, and there is a malfunction in the medical device, this could cause harm to the person using it. As a result, this could backlash on the company and it would become unreliable. It is better to be on the safer side and to do the human factors evaluation.