We're about to sound like a broken record here, but bear with us: you may want to consider adding SPF to your skincare routine if you haven't already. Of course, skin and beauty regimes are a personal choice, but scientists have found new evidence that SPF is worthwhile. It turns out that wearing sunscreen every time you leave the house can double women's chances of having younger-looking skin in old age, according to a study reported in The Times. Admittedly, the scientists who carried out the study were from Procter & Gamble, which owns Olay, so it's in their interests to tout the benefits of SPF. But still, the findings are startling. They also found that the quality of our skin as we age – how many wrinkles and blemishes we have – actually has little to do with diet, stress or genetic good fortune. It's thought that around 10% of women have skin that's biologically far younger than they are, The Times reported. Apparently, some women in their seventies even have gene activity more similar to those in their twenties. But the exact reasons why some women experience “exceptional skin ageing” are largely unclear. For the new study, P&G scientists and DNA testing company 23andMe conducted a statistical analysis of more than 150,000 caucasian women on the latter’s genetic database. Of those, 10,839 said they were often told that their skin looked ten or more years younger than their biological age, and most of these women were over 60. Their secret? Wearing sunscreen more than 75% of the time was a habit shared by a large portion of the women with younger-looking skin. This simple routine meant women were 48% more likely to be labelled a “super-ager”. Women who wore SPF for at least 90% of their daily lives were 78% more likely to be “super-agers”. Everyone knows that sunscreen has anti-ageing benefits, but the extent of these perks was unknown until now, The Times reported. What's more, the women's stress levels, sleep quality, quantity of outdoor work and intake of fast-food, fruit and vegetables were found to have no such effect on their skin. The study's findings, which haven't yet been peer reviewed or published in a scientific journal, will be presented at the American Academy of Dermatology’s annual meeting in Florida in March. The moral of the story? Regardless of whether or not these findings are watertight, slapping on some SPF each morning won't do you any harm.