If you live in the Northern Hemisphere, great news: Winter is finally over. Whether or not daily temperatures are trending up where you are, we're getting more daylight hours — and more tempting reasons to slather on some SPF.
2020 was a weird year for sunscreen, though. With COVID-19 curtailing travel and lockdowns keeping us indoors, you may not have gotten a lot of use out of that tube you picked up last. Now, of course, vaccines are bringing back the promise of a recognizably normal summer. If you've just dug up your old bottle of sunscreen, you should know some things about using it in 2021.
Like your cleaning supplies, sunscreen and tanning lotions have an expiration date. While it seems like a product that should be fairly shelf-stable, sunscreen begins to lose its efficacy after about a year. You can check its packaging for a "best by" date (it may be printed near a crease or seam), but it also doesn't hurt to inspect the product's texture. If the sunscreen is too liquid or it smells funny, it's time to toss it.
That said, if you're hanging on to last year's product because you've invested in some heavy-duty SPF, there's good news for your wallet: Because sunscreen has to be evaluated and approved by the Food and Drug Administration, even the cheapest stuff works really well. Just be sure you're using at least SPF 30 for proper protection. Beyond that, the only criteria is that you like it enough to apply every two hours.