It is good to know that on any package, by law there is an indicative period within which it would be a good practice to finish the product. It is the P.A.O (Period After Opening) indicated on the packages with the design of a small jar on which is imprinted the number of months available. This is nothing more than the period in which the manufacturer guarantees the absolute effectiveness of a given product. This does not mean that the product must necessarily have gone bad at the passing of the indicated months but simply that POTREBBE (but it is not said), be less effective.
How long can my cosmetics be stored and where should I keep it to preserve its active principles?
This is the answer to question 2.
This is the answer to question 3.