I heard or read somewhere (probably HB) that you shouldn't use sunscreen beyond the current season. I bought a few new bottles for our fam beach trip last month so I think we're stocked for the first half of summer; but need to throw out a few of last year's bottles.

What is "the rule" on sunscreen active ingredients? If there is an unopened bottle from last year, can I use it this year assuming protection level is up to par?