So, you think you know how to wash your own hair? After all, it sounds pretty straightforward. But do you really? And is your in-shower technique helping you reaching your hair’s full potential, or is it actually hindering you? “Personally, I’m a big believer in the double shampoo,” says George Northwood, who looks after the hair of Alexa Chung, Alicia Vikander and Rosie Huntington-Whiteley. Most people don’t actually get their hair truly clean when they wash it, so it ends up covered in a sort of film which leads to dullness and lack of shine over time. By shampooing twice, you have a first wash, to remove excess dirt and grime, and then a second wash to really get it squeaky clean. The main mistake we all make, according to Northwood, is to use too much shampoo in the first place, adding more and more when we find we don’t build up a sufficient lather. And washing twice doesn’t actually mean using more product – if anything you’ll find you use even less. “If you’re washing your hair twice you don’t need much shampoo at all – maybe a two-pence-sized blob for each time. The first wash probably won’t create much lather as it’s just cleansing away all of that grime and build-up. It can actually be quite half-hearted – just squirt the product into your hands, rub them together and run through the hair. I call it external cleansing. Then the second shampoo is your opportunity to really get it right into the roots and create a proper lather.” Northwood says that, washing hair every two to three days is best for most hair types, though obviously those with particular fine hair might like to wash it more often, whilst those with very curly or Afro hair can usually leave it for longer between washes. If anything you’ll probably find that you need to wash it less often if you’re doing a double cleanse, as you’re really doing a deep clean rather than just scratching the surface, he suggests. When it comes to conditioner, use your hair type as a guide. Those with very fine hair might not like to use any conditioner at all though if that’s the case, always have a Tangle Teezer on hand, whilst others will prefer to apply it only to the ends, or all over in the case of particularly dry or coarse hair. If it’s really thick, throw on loads, Northwood says. Really wringing out the hair before you apply conditioner really helps too, because excess water will only dilute the product. And apply it particularly to the ends if you’ve had balayage, or if your hair is a bit split and in need of a cut. The idea is that if you’re double-washing your hair then you’re getting it really clean, so you should be able to diagnose what it needs much more easily. For hair that gets greasy quickly, Northwood suggests a leave-in spray conditioner might feel lighter and less rich than an in-shower version. It’s also about using the right products, and finding something that suits your hair type, he says. A lot of people have a kind of hair dysmorphia and think their hair is a lot drier than it is, so they overcompensate with too-rich products. That just causes build-up, whereas if you use a lighter shampoo and conditioner, you’ll get better results. And finally, comforting words on the biggest hair-washing worry of all. If you find a fair bit of hair in your plug-hole after washing, don’t worry too much, Northwood says. Unless it really is very excessive in volume, or if you’re finding patches on your scalp where you’ve lost a lot of hair, it’s perfectly normal to shed some hair when you wash it. And that, as well as the importance of dry shampoo for those in-between days, is all you need to know.