When we are young, looking after our hair, skin and nails can sometimes seem like an afterthought. We go to bed still wearing our make-up and bite those nails as we worry about exams, boyfriends, money and our future. As for our hair, I lost count of the times I added dye of some kind, everything from bleach to spray in colours, never worrying about any damage this might do. When we are young, these things are just par for the course, and growing older seems such a long time in the future. But ageing is something that catches up with the best of us, and suddenly we need to…