Adequate time should be given to develop comprehensive design input requirements.
Unambiguous Requirements
The requirements should be unambiguous, and not only quantitative when possible, but also include expected tolerances.
Environmental conditions for the operation of the device should be specified as well as environmental storage requirements.
When possible it’s best to leverage existing industry standards, but the standards should be reviewed to ensure they cover the completeness of the requirement.
ASTM D4169
As an example, it’s common to reference ASTM D4169 for Performance Testing of Shipping Containers and Systems to establish the package conditioning and method of testing, but this standard doesn’t state specific acceptance criteria, so if those are not defined in the design input requirements, the requirement is incomplete.
The design input requirements will evolve over the course of product development, and change control is important to ensure that any design changes are reviewed for their impact on the other input requirements.
It is common for a change in one requirement to have an impact on other requirements.
In any case, changes to the input requirements should be expected.