Beauty, like fashion, feeds on novelty only to a certain extent. Cosmetics' shades and textures change seasonally with the clothes they accompany on the catwalks, but in the same way that there are some things in your wardrobe that thankfully stay pretty much the same year-in, year-out (the classic white tee, a trench coat, your pants… that kind of thing), there are a few essentials in your make-up bag that rarely alter.

That's especially true of skincare: once you find something that works, you never want to be without it again. Which is why the biggest complaint among beauty buyers is the mysterious discontinuation of fave products, cueing frantic eBay trawls to scoop up the final few precious jars.

Happily, some brands know that if people keep buying, they need to keep selling. And there are few better recommendations of a product than a good few years' presence on the shelves of the beauty hall.