Thinking about stocking up on your favorite sunscreen? You might want to check the expiration date first to make sure you’ll be able to use it while it’s still good.

Unfortunately, not all sunscreens have an expiration date on the package. For those that do, it’s not always easy to find them. Sometimes they’re stamped into the crimped end of the tube or printed on the side of the bottle. Don’t give up if you can’t find it right away.

If you can’t find an expiration date anywhere, write the date you bought it on the package and keep track for yourself. Sunscreen generally remains effective for three years after manufacturing, but it depends on how it’s been stored. The active ingredients can break down with exposure to extreme temperatures or direct sunlight, so it’s best to store sunscreen in a cool, dark place.

As long as unexpired sunscreen has been stored properly, it shouldn’t matter whether it’s been opened or not. A product that’s six months from expiration should be just as effective as one that’s twelve months from expiration.

As you’re making seasonal changes to your skincare routine, you may come across an old bottle of sunscreen and wonder if it’s still good. Here are some signs that indicate sunscreen may no longer be fully effective:

• Expiration - The stamped expiration date has passed or you purchased it more than 3 years ago.
• Consistency - The texture or thickness of the product has changed, becoming watery, grainy, or clumpy instead of smooth.
• Color - For untinted sunscreen, a yellow or brownish tint suggests the product may be expired. For tinted sunscreen, look for a shift in color (darkening or turning yellow).
• Smell - A noticeably unpleasant smell is a key indicator that sunscreen has gone bad.

It’s also wise to think about how the product was stored. If you know the sunscreen was exposed to high heat, freezing temperatures, or direct sunlight during storage, it’s best to err on the side of caution and buy a new product.

As a general rule, it’s best not to use skincare products past their expiration date. Even if the product doesn’t irritate or damage your skin, it’s not going to be as effective as it once was. This is the primary concern with expired sunscreen—that it won’t protect your skin against the sun’s harmful UVA/UVB rays.

On top of reduced efficacy, sunscreen that has expired may be more difficult to apply evenly. Exposure to heat or sunlight could cause ingredients in the formula to break down or separate, making the product watery or lumpy and hard to apply. Even application is key when it comes to sun protection, so a cohesive product is best.

If you’re ever unsure whether your sunscreen has expired or if its effectiveness has been compromised by improper storage, it’s best to err on the side of caution and buy a new product.

Proper application is the key to maximizing the protection you get from any sunscreen, but it’s also important to choose the right product to begin with. Here are some simple tips for choosing the right sunscreen and applying it properly to ensure optimal protection:

• Choose a product with at least SPF 15 protection. Sunscreen with SPF 15 blocks up to 93% of the sun’s UVB rays. Dermatologists caution against wearing less than SPF 15 but many recommend a minimum of SPF 30 which blocks 97% of UVB rays.
• Apply sunscreen 15–30 minutes before sun exposure. It takes time for chemical sunscreen products to absorb into your skin, so apply it at least minutes before you head outside. Mineral sunscreen forms a physical barrier, so it starts working immediately.
• Use more sunscreen than you think you need. A good rule of thumb to follow is to use about 1 ounce of sunscreen to cover exposed skin when wearing shorts and a T-shirt. And don’t forget to protect your face and neck!
• Reapply every two hours. Some products come with specific instructions for reapplication but most sunscreens last for about two hours under normal circumstances.
• Check the level of water resistance. No sunscreen is completely waterproof or sweatproof but some products are labeled water-resistant for up to 80 minutes. Keep in mind you’ll have to reapply after swimming or toweling off.

As you’re shopping for sunscreen, don’t forget to consider your skin type. If you have dry skin, consider a formula made with moisturizing ingredients. Sunscreen for acne-prone skin should be oil-free and non-comedogenic to avoid triggering breakouts.

When it comes to protecting your skin against environmental damage and slowing the visible signs of aging, your best bet is to wear sunscreen on a daily basis. If you’re not sure when you last replaced your sunscreen, it might be time. It’s better to be safe than sorry when it comes to sun protection!

Shop for new sunscreen and other skincare essentials at Exclusive Beauty Club. And don’t forget to check out the Exclusive Beauty Club blog for product recommendations and skincare tips.