oh i must be really wierd cos im really looking forward to the teenage years for my boys, all the years really, all them special milestones and all that. anyway, as to your problem of the teens, honestly? i'd just let them live in the sty that is there rooms. it sounds awful but even when my mum told me she'd shove everything i owned into black sacks and chuck it i never tidyed up, and you'd be suprised, my mess was always organised mess! lol. i'm still messy now but once every other week or so i go round my house and have a real cleaning frenzy. i've been nesting all week. your girls most likely think "it's my room not yours so i'll keep it how i like" but honestly, is it worth getting stressed over or pushing your daughters away over a bit of mess? just make them bring out cups and plates and what not and if they dont bring out their washing they'll soon learn it doesn't get done! like i said, it maybe organised mess so they know where everything in their room is. it always annoyed me when my rents made me tidy my room becuase all of a sudden everything important went missing and before (when i was messy) i always knew where it was! because it was organised mess! lol.
but this isn't really to me something worth stressing over. i may change my tune when the boys have horrible rooms lol