Many creams and serums boast anti-ageing effects but the best way to treat stubborn wrinkles and pigmentation is actually through preventative measures and there is no better preventative measure than SPF.In fact, incorporating SPF into your skincare routine all year round will not only slow the ageing process but it will also save your skin in the long term.Here’s why.You can still get sunburnt in winterYes, even though it may be grey out doesn’t mean you still can’t get sunburnt. Sunburns are caused by UVB rays and surprisingly, the sun's rays can still penetrate through clouds. In fact, the sun is actually closer to the Earth during the winter months. By using a broad spectrum SPF of at least 30+ you will not only be reducing your chances of getting a sunburn but you could also be saving yourself from skin cancer further down the line. If you’re into winter sports such as skiing or snowboarding then it’s extra important that you wear an SPF 30 or more as the snow and the ice reflect the sun’s rays much like the ocean.If you do happen to get sunburnt, the collagen production in your skin will also be damaged which basically puts you on a fast train to wrinkle city.Getty ImagesLong term SPF use prevents ageingIf you want to look as good as Jennifer Anniston or JLo at 50 then SPF is an absolute must. Sunscreen protects your skin from UVA rays which are known to cause skin ageing over time due to free radical damage that targets your DNA.In fact, a study was once published by the Annals of Internal Medicine that observed 903 adults under the age of 55 for 4.5 years. The group that used SPF every day ended up showing no further signs of ageing and overall showed 24% less ageing than those who didn’t wear sunscreen.UVA rays are also not absorbed by the ozone layer and 95% of UVA rays reach the ground. This is also the kind of light used in sunbeds too. So, if you’re looking to tan it’s best to stick to a spray-on one.Getty ImagesUV Rays can penetrate glassEven if you’re holed up in your home office all winter it is still important to wear SPF because UV light can still penetrate through your windows.UVB rays are largely stopped by glass but the ageing but you're still free game for damaging UVA rays. A broad-spectrum SPF is imperative to prevent these rays from ageing your skin prematurely.Least we forget this image of a woman truck driver and the one side of her face that aged faster than the other due to sun exposure.New England Journal of Medicine Tips for wearing SPFJust having SPF in your foundation isn’t enough to protect your skin. Even if your foundation sports an SPF 30 or 50 there’s no way you’ll use enough makeup to actually get the protection needed.That being said it’s best to purchase a broad spectrum (UVA and UVB) SPF that’s at least SPF 30+ or ideally 50+. Make sure it’s an SPF formulated for the face to prevent any irritation or clogged pores.Then, What you need to do is put two fingers worth of SPF on under your makeup.Sadly no SPF lasts all day or even half the day, so you need to make sure to reapply your sunscreen every two-three hours. If you wear makeup but want to get serious about your SPF practice then you can always buy a powdered SPF to reapply over your makeup.