Wet towels left in their wake, a sea of strewn clothes where there once was carpet, plates of food festering under the bed…why are teenagers so messy? A teen’s untidiness is a real bugbear for many parents and can be the source of ongoing conflict in many families. I explain why a messy bedroom is an easy, safe way for a teenager to declare their independence. And the protracted process of rewiring their brain during adolescence means that they won’t notice the mess for most of the time they're living with you. Arguing with them won't change that, but setting a few simple family rules can make things a little easier.