Where is the best place in BC to save data (dates, results, etc.) for required compliance testing associated with a product (items)?

Where is the best place in BC to save data (dates, results, etc.) for required compliance testing associated with a product (items)?
If they are in separate documents you can add them as attachment.
If the data is static for an item that does not change over time you can consider using attributes.
If they are specific to a batch of items you can consider saving them on the batch information card.