Well, I was ready to state that Ford requires an annual requalification as one of their C.S.R.'s... but, when I checked, they do not specifically require
engineering spec tests, only dimensional layout. (Ford CSR 4.42). Meanwhile my experience with GM is that they do not require periodic requalifications, at least at the system/ C.S.R. level. Of course, what matters is what your specific customers demand. I agree with the others who do not believe that there is any general requirement for periodic test requalification.
Another document that might help to define testing is the DVPR (Design
Verification Plan and Report). This is usually done by the design function, whether customer or supplier.
Regards...........Brad