Because, eyebrows can be used to 'date' you.
Obviously not like, 'date' date 
I'm currently growing my eyebrows out after a couple of disastrous threading sessions in Superdrug and now have a very nice lady keeping them tidy and offering me advice.
When we were chatting, she mentioned that the only people who wanted really thin/shaped eyebrows were middle aged women who were stuck in a rut, because 'no one' wants their brows like that, these days.
I've been looking at my friends eyebrows (which sounds weird, I know!!) and as we're all about the same age, all of us except me and my friend who's a Beauty Therapist have very, very thin brows.
I guess then, that she's right. It's made me think about all sorts of things I do/use out of habit.
I feel like a work in progress atm. I'm growing out my over highlighted hair and reckon I have about 9/10 m to go on that. My hair is cut into a long bob until they're gone.
My eyebrows haven't been this thick since my teens.
I am trying very hard to avoid ruts, but I know they're out there.
I don't want to look young/younger. I'm in my early 40s and happy with that. But does anyone have any advice on what I can do to avoid getting stuck in a rut and what sort of things I should be keeping an eye on?