PPAP samples from suppliers - requirements / best practice

Hello everyone,

I understand that we are required to keep PPAP sample parts for our customers, and our suppliers are also obligated to do the same for us, as per the references of IATF and AIAG.

However, I would like to know if there is a standard that requires us to keep the samples that we receive from our suppliers during the PPAP submission process. Should we keep these samples for the lifetime of the final products? Currently, we measure and store them after receiving them, but this is becoming a problem due to the increasing number of samples. Moreover, the storage conditions are also questionable, as there are many plastic and rubber materials that are vulnerable to environmental conditions.

Do you have any tips or best practices to share with me regarding this matter?

*if there's requirement for keeping master samples ;as one example below :
The supplier must retain at least 1 Master Sample part per cavity, mold, tool, etc., that is representative of the PPAP production run. Master samples should be identified with approval date. The master sample shall be held by the supplier over the entire life of the program. Master samples must be held for each cavity, mold, tool, etc. that has been PPAP approved. The supplier’s master sample should be available for review or to reference when part concerns arise
refer to approval requirements ; as well as master samples ; if there's no requirements ; otherwise it's useful to refer to customer key contact for any additional clarification