Qualitative Reference Standards - Assigning a re-test date

[Mouleyre]

Is there any guidance out there on setting re-test dates for qualitative standards. As you are just looking to identify the peak you could literally put years on for the re-test I guess. I have seen 5 years used as a default option but is there anything out there in the literature to say what should be used?

[Consumer Products Guy]

You can run a simple study and compare fresh stuff to the stored stuff. And document such for your records.